July 02, 2026

Another Round of Damaging Storms Could Hit Southern Ontario Thursday With Tornado Risk Increasing

July 02, 2026/ Brennen Perry

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After an active Canada Day that saw storms sweep through Southern Ontario, causing damage and power outages from widespread damaging wind gusts, Thursday may feel like déjà vu for some areas. For parts of the province, this could be the third severe weather risk of the week.

Fueling all of this active weather is the ongoing heat event, which has led to temperatures soaring into the mid to upper 30s across many locations. Thursday is expected to be similarly hot, creating more than enough instability for another round of severe weather.

While Wednesday’s risk was mainly focused on damaging wind gusts, Thursday could feature a more defined tornado risk, with one or two tornadoes possible. The focus of this tornado risk appears to be in Southwestern Ontario near the Lake Huron shoreline, along with parts of Eastern Ontario, including the Ottawa Valley.

The damaging wind gust threat also remains very present. Similar linear-like storms could sweep through a corridor from Lake Huron into the GTA, and then toward the Lake Simcoe, Peterborough and Kingston areas.

Up to Timbit-sized hail is also possible, especially across Eastern Ontario, along the Lake Huron shoreline and around the London area. In these regions, a more isolated storm mode could support a few supercell thunderstorms.

Once again, models are struggling to pinpoint exactly when and where storm development will happen. They tend to perform poorly in these types of dynamic setups, especially when storms are triggered by smaller-scale features such as lake breezes and outflow boundaries from other storms.

What we do know is where the strongest environment is located, along with a rough idea of where models are most likely to develop storms.

That begins during the afternoon, when we could see isolated cells develop from the Lake Simcoe area down toward Kingston. These storms could support a tornado risk, which is why this corridor is also highlighted on our map for tornado potential.

However, confidence is lower in this area. Not every model shows storm development, so this part of the forecast will depend heavily on whether the right triggers are in place.

Another zone of possible storm development can be found across the Ottawa Valley and Eastern Ontario during the evening. A strong shear environment could support rotation if storms are able to develop.

Similar to the afternoon Lake Simcoe risk, confidence is lower here because not all models show storm development. The threat will depend on whether storms can actually form and take advantage of the environment.

The Lake Huron storms may eventually merge into a larger complex and bring a potential late-night damaging wind gust risk through the GTA and Niagara region.

There is still some question about how long this complex would be able to maintain its strength, especially once we lose daytime heating. However, if it holds together, damaging wind gusts could once again become a concern.

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Overall, the forecast for Thursday looks quite similar to Wednesday. We have a “Strong” (Level 3/5) severe risk across a large area, but this time it also includes portions of Deep Southwestern Ontario, including the Sarnia and London areas, along with the Golden Horseshoe.

Other locations included in this risk zone are Goderich, Owen Sound, Kitchener, Hamilton, Guelph, Toronto, Newmarket, Barrie, Orillia, Peterborough, Belleville and Kingston.

This risk is being driven by the potential for strong wind gusts within this corridor, with multiple linear storms possible. If these storms can organize, they could lead to widespread wind damage. There is also the risk for up to Timbit-sized hail and one or two tornadoes.

We have a “Widespread” (Level 2/5) severe risk for Windsor, Chatham and the Lake Erie shoreline, extending into the Niagara region. There is also another “Widespread “ risk zone through Muskoka, Algonquin Park, Bancroft and the Ottawa Valley.

These areas are outside the zone most likely to see the most widespread damaging wind gusts, so the primary threat here will be driven by up to Timbit-sized hail and the risk for one or two tornadoes.

Another major concern is flooding, especially in the Ottawa Valley. This region saw significant flooding on Wednesday after more than 100 mm of rain fell in some areas. Flooding could once again become a serious issue if storms linger over the same communities or repeatedly track over the Ottawa area.

For northern sections of Central Ontario into Northeastern Ontario, including North Bay, Sudbury and Elliot Lake, we have an “Isolated” (Level 1/5) severe risk. We are not expecting widespread severe weather in this area, but with so much energy in the atmosphere, we cannot rule out an isolated pop-up storm capable of becoming severe.

July 01, 2026

Strong Severe Storm Risk Threatens Canada Day Across Southern Ontario, Damaging Winds and Isolated Tornadoes Possible

July 01, 2026/ Brennen Perry

Hot and humid weather has arrived across Southern Ontario just in time for Canada Day, with temperatures soaring into the mid-to-upper 30s, with the humidex making it feel into the 40s. While many will be heading outside to celebrate, this intense heat is also creating an atmosphere that is primed for severe thunderstorms later today.

Unfortunately, this stormy weather could put a damper on Canada Day celebrations, particularly across portions of Southwestern, Central and Eastern Ontario.

We are tracking a conditional severe weather threat for Wednesday afternoon and evening, with the risk potentially continuing into the overnight hours. The hot, humid air will provide plenty of fuel for thunderstorm development. Wherever storms are able to form, they could rapidly become severe thanks to the extremely unstable atmosphere.

In addition to isolated storm development, there is also the potential for one or more organized linear complexes of thunderstorms to move through Southern Ontario. If these systems develop and hold together, they could produce widespread damaging wind gusts across a large portion of the province.

We continue to describe today's threat as conditional because forecast models are doing a poor job of determining exactly where storms will develop. We know the environment is more than capable of supporting severe thunderstorms, but storms first need to form in order to take advantage of the available instability.

Development may be triggered by lake breeze boundaries, leftover outflow boundaries from earlier storms, or other small-scale features that are notoriously difficult to predict ahead of time. As a result, not everyone will see a thunderstorm today, but those that do could experience very intense conditions.

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As of 1 PM, we're already watching a strong complex of thunderstorms developing over Northern Michigan that is tracking toward Lake Huron and eventually Southwestern Ontario by the mid to late afternoon. If this complex is able to maintain its strength as it crosses into Ontario, it could produce widespread damaging wind gusts from areas east of Lake Huron through the Lake Simcoe region and eventually into Eastern Ontario.

Additional thunderstorms may also develop later today across Quebec before sweeping into portions of Eastern Ontario and the Ottawa Valley during the evening and early overnight hours.

Outside of these organized storm complexes, isolated thunderstorms may develop almost anywhere across Southern Ontario this afternoon and evening. If they are able to establish themselves before merging into larger clusters, a few discrete supercells could develop.

These storms would be capable of producing damaging wind gusts, hail up to the size of Timbits and an isolated tornado. While the tornado threat appears highest across Eastern Ontario, an isolated tornado cannot be ruled out anywhere in Southern Ontario today.

We have a 'Strong' (Level 3/5) severe weather risk for locations including Goderich, Kincardine, Owen Sound, Hanover, Collingwood, Midland, Barrie, Orillia, Bracebridge, Peterborough, Tweed, Bancroft, Smiths Falls, Renfrew, Ottawa, Brockville and Cornwall. This higher risk is primarily driven by the potential for widespread damaging wind gusts this afternoon and evening, although large hail and an isolated tornado are also possible.

Surrounding areas, including Grand Bend, Woodstock, Kitchener, Guelph, Hamilton, Toronto, Newmarket, Oshawa and Kingston, are under a 'Widespread' (Level 2/5) severe weather risk. These locations could also experience damaging wind gusts if storm complexes hold together, although the tornado risk is somewhat lower compared to Central and Eastern Ontario.

We also have an 'Isolated' (Level 1/5) severe weather risk across the rest of Deep Southwestern Ontario, along with the Niagara region. While storm coverage is expected to remain limited here, any storm that does develop could quickly become severe given the highly unstable environment.

Farther north, we have gone with an 'Widespread' (Level 2/5) to 'Isolated' (Level 1/5) severe weather risk across northern portions of Central Ontario, including North Bay and Sudbury. Storms that develop in this region could strengthen before tracking south and eastward into Quebec and Eastern Ontario.

The severe weather threat should gradually diminish around midnight. However, thunderstorms may continue overnight as the atmosphere will remain exceptionally unstable despite the loss of daytime heating. If a mature storm complex is able to move through overnight, isolated severe weather will remain possible, with damaging wind gusts posing the primary threat.

June 29, 2026

Multiple Tornadoes and Tennis Ball Sized Hail Possible Monday Across Manitoba and Northwestern Ontario

June 29, 2026/ Brennen Perry

After a destructive severe weather outbreak that brought violent tornadoes to Western Manitoba on Sunday, the risk shifts eastward into Winnipeg, Eastern Manitoba and Northwestern Ontario on Monday.

Based on the latest forecast data, today's storms could bring a similarly dangerous setup with the potential for significant severe weather, including multiple tornadoes, huge hail up to the size of tennis balls, destructive wind gusts in excess of 100 km/h, and areas of flash flooding.

The greatest concern is across areas just southeast of Winnipeg where we have issued a 'significant' severe weather risk. This includes Winkler, Steinbach, Kenora, Dryden, Atikokan and Fort Frances.

Storms that develop in this corridor will have the potential to rapidly become powerful supercells capable of producing all severe weather hazards. The tornado threat is expected to be highest in this zone where atmospheric conditions appear most favourable for rotating thunderstorms.

A 'strong' severe weather risk extends across the rest of South-central and Eastern Manitoba, including Winnipeg, Portage la Prairie, Carman, Killarney, Selkirk, Gimli, Ashern, Arborg, Peguis, Pine Falls, Red Lake, Sioux Lookout and Thunder Bay.

While damaging wind gusts and large hail will likely be the primary hazards across much of this area, an isolated tornado cannot be ruled out, especially across South-central Manitoba and the Interlake region where conditions may still support discrete rotating storms before they begin to organize into larger clusters.

Farther west, there is a widespread to isolated severe weather risk across Western Manitoba, including Brandon, Virden, Dauphin, Roblin and Swan River. Flooding is expected to be the biggest concern in this region as slow-moving thunderstorms could repeatedly track over the same communities.

Rainfall totals could exceed 100 mm in localized areas, leading to flash flooding. An isolated tornado also cannot be ruled out around the Brandon area during the afternoon should any storms remain isolated long enough to become organized.

**SIMULATED RADAR** - MAP FROM WEATHERBELL

Today's severe weather threat is expected to begin during the afternoon with slow-moving thunderstorms developing across Western Manitoba, particularly near the Brandon area.

These storms will move very little, increasing the risk of training thunderstorms where multiple storms repeatedly pass over the same locations.

This could quickly lead to localized flooding, but these storms may also be capable of producing large hail, damaging wind gusts and even an isolated tornado.

The primary severe weather outbreak is expected to unfold later in the afternoon and into the early evening as isolated thunderstorms develop along the international border from Winkler eastward through Southeastern Manitoba and into Fort Frances in Northwestern Ontario.

The atmosphere during this period is expected to be highly supportive of supercell development. Any storm that can remain isolated will have the potential to produce tornadoes, very large hail and destructive wind gusts.

Hail could reach the size of tennis balls in the strongest storms, which would be capable of causing significant damage to vehicles, roofs and crops.

Winnipeg sits near the northwestern edge of the greatest severe weather threat. While current guidance keeps the most dangerous storms just southeast of the city, even a small shift farther west could bring a much higher tornado risk into the Winnipeg area.

The tornado threat should gradually decrease after sunset as daytime heating fades and the atmosphere becomes less favourable for discrete supercells. However, that will not mark the end of the severe weather threat.

As the evening progresses, many of the isolated storms are expected to merge into one or more organized lines of thunderstorms. While the tornado risk will lessen, these storm lines could produce widespread destructive wind gusts capable of causing tree damage, power outages and structural damage across parts of Manitoba and Northwestern Ontario.

These storms could reach the Winnipeg and Thunder Bay regions around midnight with another round of severe weather. Although the primary concern overnight will shift toward damaging straight-line winds, an isolated nocturnal tornado cannot be completely ruled out.

The severe weather threat should come to an end across Manitoba after midnight as the storm complex moves eastward. However, portions of Northwestern Ontario may continue to see strong to severe thunderstorms into Tuesday morning before the system gradually weakens and exits the region.

June 27, 2026

Canada Day Heatwave Set to Grip Southern Ontario With Near 40°C Heat and Severe Storm Risk

June 27, 2026/ Brennen Perry

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As we approach the end of June, the weather is set to heat up in a big way across Southern Ontario with the arrival of a prolonged heatwave that is expected to bring dangerously hot temperatures by Canada Day. Based on the latest forecast data, there appears to be very little relief from the heat in the short term, with above seasonal temperatures potentially lasting through much of the week before easing closer to normal by next weekend.

The heat begins to build on Monday and Tuesday with daytime highs approaching the 30°C mark for the first time during this event. Ironically, these may end up being the “coolest” days of the week as temperatures continue to climb, with some areas potentially reaching the mid 30s by Canada Day, even before humidity is taken into account.

To make matters worse, there will be very little relief overnight. Starting Tuesday night, temperatures are expected to remain in the low to mid 20s across much of Southern Ontario. These unusually warm nights prevent homes and buildings from cooling down and give people little opportunity to recover from the daytime heat, increasing the risk of heat-related illnesses, especially after several consecutive days of extreme temperatures.

In addition to the heat, this warming trend is also expected to create an increasingly unstable atmosphere that will provide plenty of fuel for thunderstorms throughout the week. That doesn't necessarily mean storms will develop every day. Thunderstorms also require a trigger to get started, even when the atmosphere is primed.

However, the ingredients are expected to be in place for multiple rounds of thunderstorms over the coming week, including the potential for severe weather beginning as early as Tuesday.

**ESTIMATED TEMPERATURE (°C)** - MAP FROM WEATHERBELL

This heat event officially begins on Monday with daytime temperatures generally ranging from 27 to 30°C across Southern Ontario.

Keep in mind that communities located along the shorelines of the Great Lakes may remain a few degrees cooler where lake breezes develop. These breezes act like a natural air conditioner by pulling cooler air off the water and pushing it inland, offering some temporary relief for locations directly downwind.

Tuesday brings another step upward with daytime highs expected to exceed 30°C across nearly all of Southern Ontario.

The hottest temperatures are expected across Southwestern Ontario, along with the Golden Horseshoe, where the urban environment creates what is known as the ‘urban heat island’ effect. Cities contain large amounts of concrete, asphalt and buildings that absorb heat from the sun throughout the day. Unlike forests or grassy areas, these surfaces release that stored heat slowly overnight, causing cities to remain noticeably warmer than surrounding rural areas, especially during prolonged heat events.

Temperatures in these areas are currently forecast to reach between 33 and 36°C. Once humidity is factored in, it could feel more like the upper 30s or even low 40s.

**ESTIMATED CAPE** - MAP FROM WEATHERBELL

Along with the increasing temperatures on Tuesday will come a significant surge in thunderstorm energy. Forecast models are showing CAPE (Convective Available Potential Energy) values ranging from 2,000 to more than 4,000 J/kg across much of Southern Ontario. For perspective, CAPE values between 1,000 and 2,000 J/kg are already considered more than sufficient to support strong to severe thunderstorms.

While CAPE is only one ingredient needed for severe weather, it gives us an indication of how much energy is available for developing thunderstorms. The higher the CAPE, the greater the potential for storms to grow rapidly and become intense if they are able to form.

What CAPE cannot do on its own is actually produce thunderstorms. A triggering mechanism is still needed to force warm, humid air upward. Common triggers include an approaching cold front, a warm front, lake breeze boundaries, outflow boundaries from earlier storms or even the heating of the ground during the afternoon. Without one of these lifting mechanisms, the atmosphere can remain loaded with energy while little or no storm development occurs.

Since this energy is expected to remain in place for much of the week, there is a high likelihood that at least a few rounds of thunderstorms will develop. Some of these storms could certainly become severe. At this point, Wednesday and Thursday appear to offer the greatest chance for thunderstorm development, although we're still several days away and the exact timing, location and severity will become clearer as we get closer. This will need to be closely watched as it could put a damper on Canada Day celebrations.

While temperatures will cool somewhat overnight, the overnight relief will be minimal, particularly across Southwestern Ontario and the Greater Toronto Area.

Current projections suggest temperatures on Wednesday morning may struggle to fall below 25°C in these areas before sunrise, with most other parts of Southern Ontario remaining above 20°C.

These warm overnight temperatures are particularly concerning because they greatly increase the health risks associated with prolonged heat. Normally, cooler nights allow the body to recover from daytime heat stress and help homes naturally cool down.

When temperatures stay elevated all night, that recovery becomes much more difficult, especially for seniors, young children, those with chronic health conditions and anyone without access to air conditioning, such as the unhoused. Several consecutive nights of poor overnight cooling can significantly increase the risk of heat exhaustion and heat stroke.

Extreme heat can affect anyone, not just vulnerable groups, so it's important to take precautions throughout this event.

Stay well hydrated by drinking plenty of water, even if you don't feel thirsty, and try to avoid alcohol or excessive caffeine, which can contribute to dehydration.

Limit strenuous outdoor activities during the hottest part of the day, typically from late morning through the early evening, and wear lightweight, loose-fitting, light-coloured clothing whenever possible.

If you have access to air conditioning, spend time indoors where it's cool. If not, consider visiting a shopping mall, library or community cooling centre for a few hours. Also remember to check in on family members, friends and neighbours, especially older adults, young children and those with underlying health conditions.

Never leave children or pets inside a parked vehicle, even for a few minutes. Temperatures inside a vehicle can climb to dangerous levels extremely quickly!

Finally, learn to recognize the warning signs of heat-related illness. Symptoms such as dizziness, nausea, headache, heavy sweating or confusion should never be ignored. Heat stroke is a medical emergency and requires immediate medical attention!

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As we head into Canada Day, it is shaping up to be an exceptionally hot day with temperatures potentially reaching between 36 and 38°C across Deep Southwestern Ontario and portions of the Greater Toronto Area.

Once again, temperatures could be noticeably cooler near the Great Lakes, where lake breezes develop. With southwesterly winds currently expected, the greatest cooling influence will likely be found along the northeastern shorelines of the lakes.

Elsewhere across Southern Ontario, temperatures are expected to range from 33 to 36°C across much of Southwestern Ontario, around Lake Simcoe and into Eastern Ontario. Central Ontario, along with the higher elevations of the Dundalk Highlands, should remain slightly cooler with highs between 30 and 33°C.

**ESTIMATED FEELS LIKE (°C)** - MAP FROM WEATHERBELL

Humidity is also expected to continue increasing through Wednesday and Thursday, making it feel even hotter. Factoring in the humidex, it could feel well into the low to mid-40s across much of Southern Ontario. The highest humidex values are expected across Deep Southwestern Ontario and the Golden Horseshoe, although Eastern Ontario could also see "feels like" temperatures approaching 40°C.

A similar setup is expected on Thursday with many areas once again climbing into the mid-30s. Temperatures may ease slightly on Friday before a more noticeable cooldown arrives next weekend, bringing conditions back closer to seasonal values.

While the exact timing of that relief may still shift over the coming days, confidence is increasing that Southern Ontario is about to experience its most significant and prolonged heat event of the year so far. Residents should be prepared for several consecutive days of dangerous heat and stay up to date with the latest forecasts as the week progresses.

June 25, 2026

Southern Ontario Faces Severe Storm and Tornado Risk Thursday Ahead of Possible Canada Day Heatwave

June 25, 2026/ Brennen Perry

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While the latter half of June has been relatively quiet across Southern Ontario when it comes to severe weather, thanks to cooler temperatures dominating the region, that pattern is about to change in a big way. As we head into the final days of June, much warmer and increasingly humid air will begin pushing into the province, bringing with it a rapidly increasing risk for thunderstorms.

The first significant opportunity arrives on Thursday, when portions of Southwestern Ontario could see a widespread severe thunderstorm risk. An isolated severe threat may also extend farther east into parts of the Golden Horseshoe and Central Ontario.

If thunderstorms are able to develop during the afternoon and early evening, they will move into a very favourable environment capable of supporting supercell thunderstorms. These storms could produce all modes of severe weather, including toonie-sized hail or larger, damaging wind gusts in excess of 100 km/h, torrential rainfall and even a few isolated tornadoes.

The most favourable environment currently appears to be across areas including Sarnia, Chatham, Grand Bend, Goderich and London. However, isolated thunderstorms could also develop as far north as the Bruce Peninsula, east toward Lake Simcoe, and south into portions of the Greater Toronto Area. While the tornado threat decreases farther away from Lake Huron, it cannot be completely ruled out as far east as Kitchener, Hamilton and portions of the southern Georgian Bay shoreline.

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Thursday's forecast does come with one important complication. Morning showers and non-severe thunderstorms are expected to move through Southwestern Ontario before spreading into Central and Eastern Ontario during the day.

As we've seen many times before, morning convection can make or break an afternoon severe weather event. If clouds and showers linger too long, they can prevent the atmosphere from recovering enough to support stronger storms later in the day.

On the other hand, if skies clear by around the noon hour, as many of the latest models suggest, there should be several hours available for temperatures and instability to quickly rebound.

**Significant Tornado Parameter** - MAP FROM WEATHERBELL

By the mid-afternoon, the atmosphere is expected to become increasingly supportive of severe thunderstorms, with the highest risk developing between roughly 2 PM and 6 PM. The strongest combination of instability and wind shear currently appears to be centred near the Lake Huron shoreline, extending into Sarnia and Chatham.

The latest Significant Tornado Parameter (STP) data also highlights an enhanced corridor stretching from the Michigan border across Lake Huron into Southwestern Ontario. Should storms form within this corridor, they could rapidly intensify into rotating supercells capable of producing very large hail, damaging winds and isolated tornadoes.

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There remains some disagreement among the forecast models regarding exactly where storms will first develop.

Some models initiates storms as early as 3 PM across Michigan before they quickly cross into Deep Southwestern Ontario. This scenario would place communities such as Sarnia, Grand Bend, Goderich and London at the greatest risk.

Other models delay development until later in the afternoon or early evening, with storms forming closer to the Hanover to Grand Bend corridor before tracking southeast toward London, Kitchener and possibly Hamilton. Regardless of which solution verifies, the greatest tornado potential continues to favour areas along and just inland from the southeastern Lake Huron shoreline.

Additional isolated thunderstorms may also develop around Lake Simcoe and into the Greater Toronto Area during the late afternoon and early evening. While the environment in these areas appears less favourable for widespread severe weather, a few stronger storms cannot be ruled out. The primary threats would be hail up to quarter size along with isolated damaging wind gusts.

As the sun sets Thursday evening, the severe weather threat should gradually diminish as daytime heating is lost. However, scattered non-severe showers and thunderstorms may continue well into the overnight hours, particularly across Central and Eastern Ontario.

Looking beyond Thursday, the severe weather threat briefly settles down. Friday may bring a very isolated thunderstorm risk across Eastern Ontario, particularly near the Ottawa Valley, while much of the weekend currently appears relatively quiet from a severe weather perspective.

The bigger story heading into next week will likely be the return of significant heat.

Temperatures are expected to steadily climb through the weekend, with many areas approaching or exceeding 30°C by Monday. Current medium-range guidance suggests the heat could continue to intensify into the middle of next week, potentially peaking around Canada Day.

Some forecast models are indicating temperatures running between 5 and 10°C above seasonal averages, with localized anomalies approaching 15°C in parts of Ontario on Canada Day. If those projections verify, daytime highs could reach the low to mid 30s across portions of both Southern and Northern Ontario.

When combined with increasing humidity, it may feel close to 40°C in many communities.

This surge of heat and humidity will also provide plenty of fuel for additional thunderstorm development. While it is still too early to determine exactly which days will carry the greatest severe weather risk, there are increasing signs that we could be entering a much more active pattern over the next one to two weeks. Exactly when storms develop will depend on the arrival of cold fronts and other triggering mechanisms, something that will become much clearer once higher resolution models come into range.

We'll continue monitoring both Thursday's severe weather potential and the possible prolonged heat event expected next week. Stay tuned for forecast updates throughout the coming days as confidence continues to increase.

June 17, 2026

Powerful June Storm System Could Bring Damaging Winds and Isolated Tornadoes to Southern Ontario Overnight

June 17, 2026/ Brennen Perry

An unusually strong and deepening low pressure system for mid-June is set to track through the Great Lakes region overnight Wednesday and into Thursday. This powerful system will bring the potential for severe weather to a large portion of Southern Ontario, with the greatest threat occurring late tonight and into Thursday morning.

The same system is expected to produce a significant severe weather outbreak across portions of Illinois, Indiana and Michigan this afternoon and evening. In those areas, forecasters are highlighting the risk of violent tornadoes, destructive wind gusts and large hail as a potent combination of instability and wind shear develops ahead of the approaching low pressure system.

As this line of storms pushes eastward into Michigan tonight, it is expected to gradually weaken before reaching Ontario. However, weakening does not necessarily mean the severe threat will disappear.

Even in a decaying state, this line of storms could still bring impactful weather to portions of Southwestern Ontario, especially areas closest to the international border and along the Lake Huron shoreline.

Based on the latest forecast data, the primary threat appears to be damaging wind gusts in excess of 100 km/h. In localized areas, stronger wind gusts could occur if isolated downbursts develop within the line of storms. These stronger pockets of wind have the potential to cause tree damage, power outages and scattered property damage.

While the tornado threat will be considerably lower than what is expected across parts of the United States, it cannot be completely ruled out.

The atmosphere over Deep Southwestern Ontario will remain supportive of some rotation early in the night, particularly while the line of storms is still relatively organized. Any tornado risk would likely be brief and localized in nature, but the strong dynamics associated with this system mean it is something we will be watching closely.

Another factor adding complexity to this forecast is the strength of the low pressure system itself.

In addition to thunderstorm-related winds, very strong winds will be present just above the surface overnight. Normally, a temperature inversion would act as a lid and prevent those stronger winds from mixing down to ground level. Current indications suggest that inversion should remain in place for much of the night.

However, if portions of that stronger wind are able to reach the surface, isolated non-thunderstorm wind gusts in excess of 90 km/h would be possible. This risk appears highest near the shorelines of Lake Huron and Lake Erie where local effects can help enhance wind gusts.

We’ll be closely monitoring this severe weather threat throughout the evening and overnight hours.

If conditions warrant, we’ll be going live on our YouTube channel with real-time storm tracking, radar analysis, warning updates and coverage of any severe weather that develops across Southern Ontario.

Be sure to subscribe to our YouTube channel HERE and turn on notifications so you don’t miss any live coverage. Whether it’s damaging winds, tornado warnings or rapidly changing conditions, we’ll be there to keep you informed every step of the way.

Heavy rainfall will also accompany this system. Many areas will receive beneficial rainfall, but localized torrential downpours could lead to rainfall amounts exceeding 50 mm in a relatively short period of time. If storms repeatedly move over the same area, flash flooding could develop, especially in urban locations and areas with poor drainage.

The highest severe weather risk tonight stretches across Deep Southwestern Ontario and portions of the Lake Huron shoreline. This includes Windsor, Leamington, Chatham, Sarnia, Grand Bend, Goderich and Kincardine.

In these areas, storms could begin arriving as early as 8 to 9 PM and continue through the overnight hours. Damaging wind gusts remain the primary concern, although heavy rain and an isolated tornado cannot be ruled out.

As the line progresses eastward, it is expected to reach the London, Woodstock, Kitchener, Guelph, Orangeville and Hanover areas around or shortly after midnight. There remains some uncertainty regarding exactly how much strength the storms will retain by this point. However, the potential still exists for several pockets of damaging winds to survive farther inland.

The tornado threat should be lower compared to areas farther west, but strong winds and localized flooding will continue to be concerns as the line moves through.

By the time the storms reach Central Ontario and the Golden Horseshoe during the overnight hours, the severe threat should be decreasing further. That said, this remains a powerful weather system and some stronger portions of the line could still produce isolated wind gusts approaching 90 km/h.

As a result, we continue to highlight an isolated severe weather risk for Toronto, Hamilton, Niagara, Newmarket, Barrie, Orillia, Bracebridge, Peterborough and Bancroft.

Attention will then shift to Eastern Ontario during the early morning hours on Thursday. Unlike areas farther west, there are indications that the atmosphere may begin to recover somewhat as the main line approaches. There is also the potential for additional isolated thunderstorms to develop behind or ahead of the main line shortly after sunrise.

This could allow for a secondary severe weather threat across portions of Eastern Ontario, particularly near the international border and into the Ottawa Valley. This broader morning severe weather risk includes Kingston, Brockville, Smiths Falls, Cornwall, Ottawa and Picton.

Should additional storms develop within this environment, all severe weather hazards would be possible including damaging wind gusts, heavy rainfall, hail and even an isolated tornado.

Forecast confidence in the tornado threat remains lower due to the early morning timing and questions surrounding how much instability can develop. However, the environment bears watching closely given the strength of the overall weather system.

The severe weather threat is expected to gradually come to an end from west to east through Thursday morning, with most areas seeing the risk diminish by early afternoon.

Even after thunderstorms exit the region, conditions will remain quite blustery throughout the day. Strong non-thunderstorm wind gusts may continue across much of Southern Ontario as the powerful low pressure system pulls away from the Great Lakes.

May 19, 2026

Tornado Tuesday Could Bring Damaging Storms to Southern Ontario With Strong Severe Threat

May 19, 2026/ Brennen Perry

After an active, severe weather day on Monday that left widespread damage across parts of Central Ontario, especially throughout cottage country, another volatile day is shaping up across Southern Ontario.

In fact, Tuesday’s severe weather risk could end up being even stronger than Monday’s in some areas, particularly across Southwestern Ontario extending northeast toward Lake Simcoe and portions of the Golden Horseshoe.

Isolated thunderstorms are expected to develop during the late afternoon and early evening hours, bringing the potential for all modes of severe weather. This includes damaging wind gusts exceeding 100 km/h, hail up to ping pong ball size and the risk for a few tornadoes.

The primary area of concern stretches from Midland southwest toward Sarnia. Conditions in this corridor may support the development of supercells during the early stages of storm development. Supercells are rotating thunderstorms capable of producing tornadoes, very large hail and destructive wind gusts.

This early stage of the event is when the tornado and hail threat is expected to be at its highest, as storms remain isolated and are able to fully tap into the warm, unstable and highly sheared environment in place across the region.

As these storms track north and east through the evening hours, they are expected to gradually transition into a more linear storm mode. In other words, the isolated storms may begin to merge together into a squall line or broken line of embedded thunderstorms as they approach the Golden Horseshoe during the early evening.

At that point, the primary threat would shift away from tornadoes and large hail and toward widespread damaging wind gusts. However, isolated tornadoes can still occur within these types of storm lines through quick spin-ups along the leading edge, even if that is no longer the dominant concern.

The severe weather threat is expected to diminish fairly quickly after sunset, likely between 9 and 10 PM, as the loss of daytime heating weakens the atmosphere’s ability to sustain intense thunderstorms.

Behind the storms, a cold front is expected to sweep through the province overnight, bringing a sharp end to Southern Ontario’s first heat event of the year. By Wednesday morning, some areas could be waking up to temperatures back down in the single digits.

Based on the latest simulated radar data, isolated thunderstorms are expected to begin developing along a line extending from Midland southward toward Sarnia around 6 PM. However, that timing could still shift, especially since these setups can sometimes initiate earlier than forecast.

If storms are able to develop earlier in the afternoon, they would have access to an even more favourable environment, potentially increasing the severe weather risk.

Regardless of exactly when storms first form, the expectation is that they will remain fairly isolated for the first few hours of their lifespan as they track east of Lake Huron and northeast toward regions surrounding Lake Simcoe.

There is particular concern for the Midland to Kawartha Lakes corridor, where several model runs continue to indicate the potential for a dominant supercell to develop and track through the region.

Given that the strongest atmospheric conditions are expected to overlap in this area, any storm that develops there could become quite intense quickly, with the potential for tornadoes and very large hail.

Additional severe thunderstorms may also develop farther southwest and track through areas including London, Kitchener, Orangeville and Barrie during the dinner hour.

Farther east, a few isolated storms may also develop near Bancroft and the Ottawa Valley. However, the environment in those areas does not currently appear to be quite as favourable for widespread severe weather, so confidence in storm intensity there remains lower.

As the evening progresses and daylight fades, the isolated cells are expected to begin merging together into a more organized line of storms while gradually weakening as they approach the Greater Toronto Area.

These storms could certainly remain severe into the evening hours, but the primary threat would likely transition toward damaging wind gusts, which is common with linear storm events.

That does not mean the tornado threat disappears entirely though. An isolated QLCS tornado cannot be ruled out within the line as it tracks eastward through the evening.

QLCS stands for “quasi-linear convective system,” which is essentially a line of thunderstorms capable of producing brief, fast-forming tornadoes embedded within the line itself. These tornadoes are often difficult to detect and can develop with little warning.

The hail threat, however, is expected to decrease significantly by this stage of the event as storms lose their isolated structure and strong updrafts.

Overall, the severe weather risk should come to a fairly quick end shortly after sunset as the atmosphere stabilizes. While a few overnight thunderstorms may linger behind the main line, they are expected to remain below severe limits.

Looking ahead to the rest of the week, Southern Ontario’s brief taste of summer-like weather is set to come to an abrupt end behind Tuesday night’s cold front.

Temperatures are expected to tumble overnight, with some parts of Southwestern and Central Ontario potentially waking up to single-digit temperatures by Wednesday morning. In fact, there may even be some frost risk later this week across portions of Central Ontario as cooler air settles back into the province.

May 18, 2026

Multi-Day Severe Storm and Tornado Risk Targets Southern Ontario Alongside Summer-Like Heat

May 18, 2026/ Brennen Perry

Southern Ontario is about to get its first real taste of summer weather in 2026, and it’s arriving with a potentially stormy side effect.

Temperatures are expected to soar into the upper 20s and even near 30°C in some areas on both Monday and Tuesday as a surge of warm and humid air spreads across the province. While this early-season heatwave will be relatively brief, it’s expected to create a volatile atmosphere capable of producing two consecutive days of severe thunderstorms across parts of Southern Ontario.

From large hail and damaging wind gusts to the possibility of isolated tornadoes, there’s a lot to track over the next 48 hours. Our team will be providing extensive live coverage throughout both severe weather risks on our YouTube channel, with real-time storm tracking, warning updates, radar analysis and live storm chasing coverage as storms develop. If you’re looking for in-depth storm coverage in Ontario, Instant Weather will be the place to be over the next two days.

The first round of potentially severe weather is expected to develop during the mid to late afternoon hours on Monday as strong storms over Michigan begin to track into the Lake Huron and Manitoulin Island area around 3-6 PM. These storms are likely to merge into a single line with embedded cells as they cross the Bruce Peninsula and into regions around the northern and eastern shoreline of Georgian Bay. Early in their lifespan, they could present all storm hazards, including damaging wind gusts and hail up to the size of toonies.

As these storms move into Central Ontario, including much of Ontario’s cottage country such as Muskoka, North Bay and Algonquin Park, the environment could become capable of supporting a brief spin-up tornado. There is still some uncertainty regarding the tornado risk as some models suggest the storms may arrive later in the evening, after the most favourable tornado environment begins to weaken.

A secondary cluster of storms may also approach regions further south and west, including Deep Southwestern Ontario and along the eastern Lake Huron shoreline during the late afternoon and early evening hours. At this point, damaging wind gusts appear to be the primary threat in these areas, while the hail and tornado risk looks lower, although it can never be completely ruled out.

As these clusters of storms track northeast, they are expected to gradually weaken by the late evening as the daytime heating fuelling them begins to fade away. Due to this, there remains some uncertainty regarding how far east the severe risk will extend, as it will largely depend on how quickly the storms move before losing access to the strongest instability.

We have gone with a slight (level 2 out of 5) severe thunderstorm risk for locations including Windsor, Leamington, Chatham, Sarnia, Grand Bend, Goderich, Kincardine, Hanover, Owen Sound, Wiarton, Tobermory, Collingwood, Midland, Bracebridge, Huntsville, Parry Sound, Britt, Manitoulin Island, Sudbury, North Bay, Algonquin Park and Deep River. This is the area most likely to experience the strongest storms today, but it’s important to remember that not everyone within the risk zone will necessarily see severe weather.

A marginal (level 1 out of 5) severe thunderstorm risk includes London, St. Thomas, Woodstock, Tillsonburg, Brantford, Kitchener, Guelph, Orangeville, Barrie, Orillia, Bancroft, Pembroke and Renfrew. If severe weather develops in these areas, it will most likely be isolated damaging wind gusts associated with weakening storms during the evening hours.

Non-severe thunderstorms are also possible for the Greater Toronto Area and parts of Eastern Ontario. While widespread severe weather is not expected there at this time, any storms that do develop could still produce frequent lightning, heavy downpours and locally gusty winds.

Turning towards Tuesday, the overall severe weather setup may become even more favourable and widespread, but confidence in storm development itself remains lower.

A very warm and unstable atmosphere is expected to build across Southern Ontario throughout the afternoon and evening hours. If storms are able to form, they could rapidly intensify and become severe across Southwestern Ontario, the Golden Horseshoe and areas surrounding Lake Simcoe, along with Central and Eastern Ontario. This setup would support all severe weather hazards, including damaging wind gusts, large hail and isolated tornadoes.

However, forecast models continue to struggle with exactly where storms will initiate and whether they will develop at all. That uncertainty is preventing a more aggressive severe weather outlook at this time.

Current indications suggest isolated thunderstorms may first begin developing around Grey-Bruce during the mid-afternoon hours before slowly tracking southeast toward regions around Lake Simcoe between roughly 2-5 PM. Additional thunderstorm development may also occur farther southwest and along the Lake Erie shoreline later in the day.

Like Monday, these storms will be heavily dependent on daytime heating and atmospheric instability. Once the sun begins to set around 8-9 PM, any storms that have developed are expected to gradually weaken fairly quickly.

At this time, it appears the Ottawa Valley may remain outside the main severe weather risk on Tuesday. However, that could still change in our final outlook as confidence increases regarding storm development and storm coverage. The atmosphere across Eastern Ontario will still be somewhat supportive of marginally severe thunderstorms, but confidence is currently not high enough to formally include those regions within the isolated severe risk area.

May 16, 2026

Victoria Day to Bring Early Tease of Summer to Southern Ontario With 30°C Heat and Severe Storm Risk on Monday

May 16, 2026/ Brennen Perry

After a chilly and wet start to May across Southern Ontario, it finally looks like summer is ready to make an appearance, just in time for the Victoria Day long weekend.

The first half of the month has certainly felt more like an extension of early spring than the lead-up to summer. We’ve dealt with multiple rounds of widespread frost, temperatures consistently running below seasonal, and even reports of wet flurries in some areas.

While we did get a brief taste of severe weather with Canada’s first confirmed tornado of 2026 on May 9th near Lucan (northwest of London), the summer-like warmth has been hard to come by. That’s about to change!

The Victoria Day long weekend, often considered the “unofficial start of summer” in Ontario, is expected to fully live up to the title this year. A significant warm-up is set to spread across Southern Ontario through the weekend, peaking on Monday with widespread summer-like heat and humidity.

The hottest temperatures on Monday are expected to be found in Deep Southwestern Ontario extending into the western GTA and Niagara region, including Windsor, Chatham, Sarnia, London, Grand Bend, Woodstock, Brantford, Hamilton and Niagara Falls. Daytime highs in these areas are likely to range between 30-33°C with humidex values potentially approaching 35°C at times.

While many will be excited to finally enjoy some summer-like weather, it’s important to remember that the first major heat event of the season can be particularly stressful on the body. Be sure to stay hydrated, limit strenuous outdoor activity during the hottest part of the day, and never leave children or pets unattended in vehicles. Pets can also quickly overheat on hot pavement, so it’s a good idea to check surfaces before heading out for a walk.

For much of the rest of Southern Ontario, daytime highs are expected to range between 27-30°C, with the humidity making it feel into the low 30s. This includes Toronto, Kitchener, Barrie, Muskoka, Peterborough, Kingston and Ottawa.

The higher elevations of the Dundalk Highlands are likely to remain a few degrees cooler, with areas like Orangeville and Shelburne expected to top out closer to 24-27°C.

Meanwhile, temperatures directly along portions of the Lake Erie and Lake Ontario shoreline may stay noticeably cooler thanks to developing lake breezes. Southwest winds coming off the still-cool lake waters will help suppress temperatures near the shoreline through the afternoon hours.

As a result, locations such as Picton, Cobourg, Oshawa, Fort Erie, Port Colborne, Port Dover, Turkey Point and Leamington could struggle to climb much beyond the low 20s despite the intense heat further inland.

A similar cooling effect is expected along the Bruce Peninsula, Manitoulin Island and parts of the northern Georgian Bay shoreline. Locations such as Britt, Manitoulin Island and Tobermory are also expected to remain closer to 20°C.

The heat is expected to continue into Tuesday with similar daytime highs before a cold front sweeps through later in the week, returning temperatures closer to seasonal or even slightly below seasonal levels.

Another concern with the return of summer-like heat will be the increasing fire danger across parts of the province. According to the latest forecast from the Canadian Wildland Fire Information System, portions of Deep Southwestern Ontario could see fire danger levels reach high or even extreme on Monday, thanks to the combination of hot temperatures, dry conditions and gusty winds.

With many people planning campfires and fireworks for the Victoria Day long weekend, it’s especially important to use extra caution with any open flames. Be sure to follow all local burning regulations and fire bans, and check with your local municipality before setting off fireworks or lighting a fire. Under high or extreme fire danger conditions, even a small spark can quickly spread and become difficult to control.

With the return of summer-like heat also comes the return of increasing atmospheric instability, which can help fuel thunderstorms. The next few days are expected to feature multiple opportunities for thunderstorms across parts of Southern Ontario.

The first round is expected Sunday night into Monday morning as a batch of non-severe nocturnal thunderstorms potentially tracks through areas near Lake Huron extending into Central and Eastern Ontario.

That activity may help set the stage for another round of storms later Monday afternoon and evening. At this point, the greatest risk for isolated severe thunderstorms appears to be focused east of Georgian Bay around Muskoka, Parry Sound and Algonquin Park. A line of storms may also develop over Michigan and track into Deep Southwestern Ontario later Monday night into Tuesday morning, but the exact intensity remains unclear by the time it reaches the border.

Locations that could potentially see isolated severe storms on Monday include Goderich, Kincardine, Hanover, Owen Sound, Wiarton, Tobermory, Collingwood, Midland, Orillia, Bracebridge, Huntsville, Parry Sound, Britt, North Bay, Sudbury, Algonquin Park, Bancroft, Pembroke and Deep River.

It remains too early to determine the exact storm mode and whether any tornado risk will develop. For now, all severe weather hazards remain possible including damaging wind gusts, large hail and torrential rainfall.

A more detailed severe weather outlook, including specific risk categories and hazard breakdowns, will be issued Sunday night or Monday morning once higher resolution forecast models come into range and confidence improves on the exact storm setup.

We’re also monitoring the potential for a more widespread severe thunderstorm risk on Tuesday as a cold front approaches the region later in the day.

However, there is still some uncertainty regarding the exact timing of the cold front. If it arrives later Tuesday afternoon or evening, there would likely be enough daytime heating available to support stronger storms. If the front arrives overnight or earlier in the day, it could significantly reduce instability and limit the severe weather potential.

At this point, isolated thunderstorms remain possible Tuesday afternoon and evening, but the exact location and intensity of the strongest storms remains uncertain.

May 09, 2026

🔔⛈️ Severe Thunderstorm Risk Today Focused on Southwestern Ontario with Damaging Winds, Large Hail & an Isolated Tornado Cannot be Ruled Out

May 09, 2026/ Adam Skinner

Southern Ontario is facing a fairly widespread thunderstorm risk this afternoon and evening, Saturday, May 9, 2026 with the potential for isolated severe thunderstorm activity.

The strongest potential for severe thunderstorms will be in the yellow region, especially between roughly 3 and 7 PM across deep Southwestern Ontario. Storms in this area could bring damaging wind gusts, large hail around 1 to 3 cm in size, frequent lightning, and localized flooding. Isolated tornado activity cannot be ruled out in the yellow region today as well, so we’ll be live streaming on our YouTube channel to monitor for any signs of organized rotation.

In the green region, the main threats will be strong wind gusts, hail, frequent lightning, and torrential rainfall, which could create difficult travel conditions for many. There is a small chance that wind gusts or hail in the green region could briefly reach severe limits, which is why we’ve highlighted it for an isolated severe risk.

We’ll also be sending out Environment Canada’s official watches and warnings through our free InstantWeather app, along with possible custom notifications if we spot anything worth notifying.

And in some exciting news, we’re planning to launch our completely revamped free app on June 1st! It includes dark mode, a widget, and a full rebuild from the ground up for better performance, reduced battery usage, and an improved experience overall. We’ve also built the original app experience into the new version for those who prefer it. :)

More details coming ASAP. Woohoo!

April 07, 2026

Southern Ontario: School Bus Cancellations and Closures for Tuesday, April 7, 2026

April 07, 2026/ Alannah Campbell

Please refresh your page every few minutes to receive the latest update

Cancellation & Closure Map (English Public and Catholic Schools)

Please note: School board boundaries are a rough estimate. Don’t use this map to determine what school board or weather zone you live in as accuracy isn’t guaranteed.

Green = No Cancellations
Red = Cancellations (Click for More Details)
Purple = School Closures (Click for More Details)

List of Cancellations & Closures

English Public and Catholic Schools

Kawartha Pine Ridge Public & Peterborough Victoria Northumberland Clarington Catholic: Bus and transportation service is cancelled to Peterborough and Northumberland County schools.
Near North Public & Nipissing-Parry Sound CathoIic: School Bussing is cancelled in the East Parry Sound South zone
Renfrew County Public & Renfrew County Catholic: Zone 4 Madawaska area transportation services have been cancelled.
Tri-Board: School bus and taxi transportation is cancelled in North Hastings & Centre Hastings weather zones today.

French Schools

Conseil catholique MonAvenir: Busses are cancelled for schools in Peterborough
Le Conseil scolaire public du Nord-Est de l’Ontario (CSPNE) & Conseil scolaire catholique Franco-Nord: School Bussing is cancelled in the East Parry Sound South zone

April 06, 2026

Up to 5 to 10 cm of Snow and Wind Chills Near -15°C as ‘Third Winter’ Arrives in Southern Ontario This Week

April 06, 2026/ Brennen Perry

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Since the arrival of astronomical spring, the weather has certainly matched the season across Southern Ontario. We’ve seen multiple days of double digit temperatures along with the typical spring thunderstorms. However, as we head into the first full week of April, it appears that our ‘3rd winter’ is on the horizon, bringing with it a blast of cold and snowy weather that many thought was behind us for the season.

The good news is that there is light at the end of the tunnel. This blast of wintry weather will only be temporary, with a return to more seasonal conditions expected towards the end of the week.

It certainly isn’t going without a fight. A heavy burst of snow late Monday and continuing into Tuesday may lead to tricky travel conditions as people head back to school and work after the Easter long weekend. You’ll also need to dust off those winter coats again as temperatures plunge overnight Monday, bringing a brief return to wind chills near -15°C in some parts of Southern Ontario.

While we aren’t expecting widespread significant snowfall accumulation from this late season system, the timing could still leave roads snow covered and slushy ahead of the Tuesday morning commute. The snow will fall within a short timeframe and could be quite heavy at times, leading to reduced visibility and some blowing snow.

Most areas are only expecting to see a few centimetres of snow by the time it tapers off early Tuesday afternoon. However, some pockets, especially across parts of Central and Eastern Ontario, could exceed the 5 cm mark and end up seeing between 5 and 10 cm.

The main caveat is that temperatures will still be near the freezing mark when the bulk of the snow is falling late Monday into early Tuesday morning. This means some of it may melt on contact with the ground before being able to accumulate. As a result, actual totals will vary significantly and could fall short of the 5 to 10 cm mark in some areas if temperatures end up slightly warmer.

An area of heavier snow is expected to track into regions around Lake Huron and into Northeastern Ontario sometime during Monday evening. This could start as a rain and snow mix with temperatures still near freezing, especially near Lake Erie and Deep Southwestern Ontario, but should switch over to snow later in the evening.

Even though we are less than six hours away from the start of the snow, models still disagree on the exact intensity and placement. There also appear to be dry slots within the precipitation, which could lead to some areas getting completely missed. At the same time, some moisture from the lakes may enhance snowfall rates in localized areas.

**Hourly snowfall rates (cm)** - MAP FROM WEATHERBELL

By the pre dawn hours on Tuesday, the snow will become more widespread, extending around the Lake Huron shoreline and into Central and Eastern Ontario.

The heaviest pockets of snow appear likely to track from Muskoka through Peterborough and into the Kingston corridor. This could lead to rapid accumulation if temperatures are cold enough to limit melting. Expect poor driving conditions overnight and early Tuesday morning in this area, with sudden whiteout conditions possible.

Around Lake Huron, we could see a brief return of lake effect streamers affecting the London, Goderich and Kincardine area through the morning hours. This may also include the southern shoreline of Georgian Bay.

Wind gusts approaching 50 to 70 km/h may lead to blowing and drifting snow in these areas. While overall accumulation is expected to be limited, even a small amount of snow in exposed rural areas can make travel difficult when paired with strong wind gusts.

We are expecting all of the snow to taper off by early Tuesday afternoon as the main system moves out of Eastern Ontario. Winds will also begin to lighten, shutting off any lingering lake effect activity from Lake Huron and Georgian Bay.

Even if you don’t see accumulating snow, you will still get a taste of Southern Ontario’s third winter over the next few days in the form of bitterly cold temperatures.

It will pale in comparison to the cold we dealt with earlier this year, but it may feel more brutal after many areas hit 20°C just a few days ago. Now, we’re looking at temperatures between -5°C and -10°C to start the day on Tuesday. Factoring in the wind chill, many areas will feel into the negative double digits, with parts of Central and Northeastern Ontario ranging from -15°C to -20°C Tuesday morning.

Thankfully, temperatures are expected to quickly improve by Wednesday and Thursday. Daytime highs will inch back above the freezing mark and could even reach double digits by the end of the week in some areas.

As mentioned, this event will feature significant variation in snowfall totals across the region, making it difficult to pinpoint exact amounts. This is due to both the scattered nature of the snow and temperatures hovering near freezing, along with ground warmth from the recent mild weather. That means not everyone will see accumulating snow, even within the highest forecast zone.

The zone of highest accumulation is expected to include much of Central Ontario extending into Eastern Ontario south of the Ottawa Valley. This includes Kingston, Belleville, Peterborough, Bancroft, Orillia, Bracebridge, Huntsville, Algonquin Park, Parry Sound, Sudbury and Elliot Lake. These areas could see general totals of 5 to 10 cm, with localized pockets potentially exceeding that up to 15 cm. Not everyone within this zone is guaranteed to see 5 cm, as local temperatures will determine how much of the snow is able to stick.

A few centimetres of snow are expected around the Lake Huron and Southern Georgian Bay shoreline, including Grand Bend, Goderich, Kincardine, Owen Sound, Hanover, Collingwood and Barrie. Around 2 to 5 cm is possible here, but due to the nature of lake effect snow, some localized areas could see up to 8 cm, while others may get completely missed.

A trace to a light dusting of snow is expected for Deep Southwestern Ontario into the Golden Horseshoe, along with the Ottawa Valley. Much of this is unlikely to stick to the ground.

No matter how much snow you receive, it will almost certainly be gone within 24 hours thanks to temperatures rising above freezing by Wednesday. That means you likely won’t need to bring those shovels back out of storage.

March 31, 2026

Large Hail and Isolated Tornado Risk on Tuesday for Southwestern Ontario and Golden Horseshoe With Widespread Severe Storm Threat

March 31, 2026/ Brennen Perry

Southern Ontario faces the first widespread severe weather threat of 2026 on Tuesday, which is already underway as overnight storms carrying a flooding and hail risk developed around midnight.

While the severe risk overnight is fairly limited, it could still be quite a noisy night across Southwestern Ontario and into the Golden Horseshoe.

The main risk on Tuesday is expected to take shape Tuesday afternoon and continue into the evening. A complex of storms is set to develop by early afternoon over Michigan and gradually slide into Southwestern Ontario through the afternoon.

Ahead of this line, rising temperatures reaching into the 20s in some areas of Southwestern Ontario will provide sufficient heating to fuel increasing intensity as the line builds to the southwest.

The strongest storm environment appears to be focused on Deep Southwestern Ontario such as Windsor, Chatham, Sarnia and the London region. This is where we could see more isolated storm development rather than the more linear development to the north. As such, we have gone with a slight severe risk.

That may allow for a few rotating storms, and therefore an isolated tornado can’t be ruled out. It’s certainly not the main risk though.

The primary threat is large hail that could approach Timbit size, along with isolated wind gusts of 90 to 100 km/h.

There is a marginal severe risk for areas east of Lake Huron and up to the Niagara Escarpment where there will be a sharp cut off in temperature. This will lead to storms quickly fizzling out as they lose access to the heat that was fueling them.

This includes Goderich, Kincardine, Hanover, Orangeville, Kitchener, Guelph, Hamilton, Brantford and the Niagara region.

For the rest of Southern Ontario, non severe thunderstorms are expected through the afternoon and evening across Central and Eastern Ontario, but they will be on the weaker side due to temperatures remaining in the single digits. Small hail could still be a threat, with the colder air making it possible for weaker updrafts to sustain larger than usual hail.

Another round of storms may impact Deep Southwestern Ontario during the late evening, but it is questionable how strong they will be because they will be occurring after sunset and the storms will lose access to daylight heating.

All storm risk should diminish in all areas by midnight as colder air ushers temperatures back into the single digits for Wednesday.

March 19, 2026

Winter Crashes the First Day of Spring, Snow and Ice to Disrupt Friday Commute in Southern Ontario

March 19, 2026/ Brennen Perry

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With the official start of astronomical spring arriving on Friday, Southern Ontario is set to enter a weather roller coaster. It begins with a heavy burst of messy, mixed precipitation that could impact the Friday morning commute. At the same time, parts of Southwestern Ontario will welcome the first day of spring with double-digit temperatures, with some areas potentially flirting with the 20°C mark.

As temperatures begin to rise on Friday, a fast moving system will push across Southern Ontario ahead of the warmer air. With surface temperatures still below freezing early in the day, some of the precipitation will fall as snow, ice pellets, and even freezing rain.

While the heaviest precipitation will only last for a few hours, the timing could not be worse. It is expected to peak across Southwestern Ontario and the Golden Horseshoe during the mid to late morning hours. This will likely create slippery road conditions right in the middle of the morning commute.

There is still some uncertainty when it comes to exact precipitation types, as temperatures will gradually rise through the day. In many areas, it will likely begin as snow, then transition to ice pellets, followed by a period of freezing rain, before eventually changing over to regular rain. South of Lake Simcoe, the main transition will be from ice pellets to freezing rain.

In higher elevations such as the Dundalk Highlands and the Oak Ridges Moraine, slightly cooler temperatures may allow freezing rain to last longer and become more impactful, with greater potential for ice accretion.

Across Central and Eastern Ontario, heavy snow from the late morning into the early afternoon is expected to lead to quick accumulation. Many areas could pick up around 10 cm, give or take 5 cm depending on how much mixing occurs, especially closer to Lake Simcoe and Lake Ontario. This snow is likely to fall rapidly within a 2 to 3 hour window, with snowfall rates exceeding 5 cm per hour at times. Expect brief whiteout conditions and fast accumulation while it is falling.

Precipitation is expected to move into Southwestern Ontario around sunrise, then gradually spread eastward into the Golden Horseshoe and Central Ontario by the late morning, roughly between 8 and 10 am. As it arrives, it will encounter a layer of cold air near the surface that will be slow to move out. This will help set up a swath of winter weather, with snow stretching from Muskoka into Eastern Ontario, and a mix of ice pellets and freezing rain developing around Lake Simcoe and into Peterborough.

More persistent freezing rain is likely across higher elevations northwest and north of the Greater Toronto Area. For areas closer to Lake Ontario and outside of the higher terrain, freezing rain will be more limited, generally lasting an hour or two during the mid to late morning before temperatures rise.

**HOURLY SNOWFALL RATE (CM)** - MAP FROM WEATHERBELL

The snow band moving through Muskoka, Peterborough, and into Eastern Ontario could be quite intense at times. Snowfall rates may briefly reach 3 to 6 cm per hour late in the morning into the early afternoon. Some of this precipitation may fall as ice pellets, which could reduce overall snow totals slightly.

As temperatures continue to rise, areas around the Greater Toronto Area should transition to regular rain by around midday. However, a corridor of freezing rain may develop from Barrie through Peterborough and into Kingston. This, combined with slushy snow, could result in very poor road conditions with icy patches.

Precipitation will gradually taper off through the afternoon, with Eastern Ontario likely being the last region to see it come to an end.

Temperatures will vary significantly across the region on Friday afternoon. Deep Southwestern Ontario, including Windsor, Leamington, and Chatham, could surge well into the double digits and approach 20°C. Meanwhile, Central and Eastern Ontario may struggle to climb above the freezing mark.

The good news is that most areas expecting any notable ice accretion should see temperatures rise above freezing by the afternoon. This will help reduce the overall impact on tree branches and power lines, and also improve road conditions as the day goes on.

Overall impacts will vary quite a bit depending on location. Across Central and Eastern Ontario, the main story will be heavy snow. Accumulations are expected to range from 5 to 10 cm, with some areas potentially approaching 15 cm. This includes regions north of a line from Gravenhurst to Brockville, including Muskoka, Haliburton, Bancroft, Pembroke, Renfrew, Smiths Falls, Ottawa, and Cornwall.

South of this line, a narrow corridor from Simcoe County through Kawartha Lakes, Peterborough, and into Kingston will likely see a mix of everything. This includes a period of snow, followed by ice pellets, and finishing with some freezing rain. Total accumulation in this zone will range from 2 to 10 cm, with higher amounts toward the northern edge.

The most persistent freezing rain is expected across higher elevations, including areas such as Flesherton, Shelburne, Arthur, Fergus, Guelph, Orangeville, Vaughan, and Newmarket. These areas could see between 2 and 6 mm of ice accretion.

Closer to Lake Simcoe, including northern York Region into Durham Region, around 2 to 4 mm of icing is possible, along with some ice pellets.

Near the Lake Ontario shoreline, including the Greater Toronto Area into Hamilton, Kitchener, Perth, and Grey Bruce, freezing rain is expected to be brief. Most areas will see less than 2 mm of ice, and impacts should be limited as temperatures rise above freezing relatively quickly.

For areas along the Lake Huron and Lake Erie shorelines into Deep Southwestern Ontario, this system will stay primarily on the rain side, with little to no winter precipitation expected.

March 16, 2026

Winter Roars Back Across Southern Ontario Tuesday With Up to 30 cm of Snow and -20°C Wind Chills

March 16, 2026/ Brennen Perry

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It sure may have felt like winter was behind us for the first half of March, but the second half of the month will serve as a snowy and chilly reminder of what Mother Nature is still capable of across Ontario.

We certainly saw that over the past 24 hours in Northern Ontario, where some communities were buried under more than 50 cm of snow from a late-season winter storm. And over the next 24 hours, Southern Ontario will join them in sharing some of that snowy misery.

The system that brought the heavy snow to Northern Ontario has now begun to move out over Quebec. As it exits the region, it is set to usher in a blast of cold air late Monday evening into the overnight hours. That includes the return of a familiar word, snow squalls.

Moisture from a separate system tracking along the northeastern United States is expected to push into Eastern Ontario and areas around Lake Ontario starting Monday evening. With temperatures dropping quickly behind the departing system, that precipitation is likely to fall in the form of heavy snow.

That snow could become quite intense at times across Central and Eastern Ontario, with snowfall rates of 3 to 5 cm per hour in the heaviest pockets. While it should taper off by the early morning hours on Tuesday, just a few hours of that intensity could be enough to bring 10 to 20 cm by Tuesday morning in some communities.

Further west, plunging temperatures will combine with the now partially ice-free waters of Lake Huron and Georgian Bay to bring a brief resurgence of snow squall activity. While it will not last all day, these squalls could bring locally up to 20 to 30 cm of snow before they wrap up by late Tuesday afternoon. Wind gusts peaking Tuesday morning up to 50 to 70 km/h are likely to combine with the snow squall activity to produce blowing snow and potentially disruptive travel in the snowbelt areas.

Aside from the snow, Tuesday will start off on a very chilly note with wind chills dropping below -20°C in some areas during the morning hours.

Precipitation has already begun to spread into Eastern Ontario as of early Monday evening and is expected to continue increasing in intensity over the next several hours. The worst conditions are likely to occur around midnight, when snowfall rates could approach 3 to 5 cm per hour, especially between Peterborough and Kingston.

While this will only last for a few hours, that kind of snowfall in such a short timeframe is likely to make travel difficult during the overnight hours as road crews struggle to keep up. The snowfall intensity appears lighter further east around Cornwall and Ottawa, where totals will be more limited.

Lake effect activity is also expected to begin organizing, starting with Lake Huron. There is still some uncertainty around the Georgian Bay component. The system affecting Eastern Ontario could track far enough west to influence wind direction off Georgian Bay, which may delay or even limit the onset of snow squalls in that region.

By the early morning hours of Tuesday, Eastern Ontario will see the steady snowfall taper off as it shifts into Quebec.

Instead, the focus will turn to strengthening lake effect activity off Lake Huron and Georgian Bay. Again, there is some disagreement on how intense the Georgian Bay squall will become. If it does develop properly, it appears most likely to focus somewhere along the Midland to Orillia corridor.

The Lake Huron activity will initially target Bruce and Grey counties, at times extending into northern Huron and Perth counties, along with portions of Wellington and Dufferin counties.

Another major concern is that this lake effect activity will be accompanied by gusts approaching 50 to 70 km/h at times, especially near the shoreline and in flat, exposed areas. That can lead to significant reductions in visibility due to blowing snow and may even briefly meet blizzard criteria in some areas east of Lake Huron.

It is very likely that the usual roads vulnerable to blowing snow across Grey Bruce, Huron and Perth counties may need to be shut down for a period of time on Tuesday. Expect significant delays and consider avoiding travel if possible, especially during the morning and early afternoon.

Heading into Tuesday afternoon, the winds fueling the lake effect activity are expected to gradually diminish, starting with Georgian Bay. That will likely allow any activity off Georgian Bay to slowly fizzle out by early afternoon.

For Lake Huron, the activity is likely to drift south of Grey Bruce and focus more on portions of Huron and Perth counties. It may persist for several hours through the afternoon before weakening closer to the dinner hour.

If the snowfall is not enough to set the winter mood, it will certainly feel like it as a surge of Arctic air settles over Southern Ontario overnight into Tuesday.

Many areas are expected to drop below -10°C by Tuesday morning. With the wind chill, it could feel closer to -25°C in some locations, especially east of Lake Huron into Central Ontario and parts of Northeastern Ontario.

As is usually the case with lake effect snow, it can be very difficult to pinpoint the hardest hit regions. These snow bands can be narrow and highly localized, meaning one community could see significant accumulation while another just down the road sees very little.

With that in mind, the heaviest snowfall totals are most likely somewhere in the Port Elgin, Hanover, Minto, Mildmay, Kincardine, Point Clark and Wingham zones. We are forecasting 20 to 30 cm in this corridor, but there is a chance that localized areas could see as much as 35 to 40 cm if a band locks in place for several hours.

Surrounding areas, including Goderich, Clinton, Exeter, Mitchell, Stratford, Listowel, Arthur, Flesherton, Meaford, Chatsworth, Owen Sound, Wiarton and Lion’s Head could see around 10 to 20 cm. Some of these communities may fall short of that depending on how far inland the lake effect bands extend and how long they persist.

For the Georgian Bay squall, we are forecasting 10 to 20 cm for Midland, Orillia and Washago. Barrie sits right on the line and could go either way. If 10 cm or more falls in Barrie, it would most likely be in the north end, with lesser amounts toward the south. Should the Georgian Bay activity exceed expectations and organize more than current guidance suggests, localized pockets of 25 to 30 cm cannot be completely ruled out. However, it could just as easily struggle to reach 10 cm.

In Eastern Ontario, the system is expected to deliver a general 10 to 15 cm in locations including Peterborough, Belleville, Kingston, Bancroft, Deep River, Renfrew and Pembroke. Some areas, especially north of Lake Ontario between Peterborough and Kingston, may pick up closer to 20 cm where the heaviest snowfall rates set up overnight.

Less than 10 cm is expected for Ottawa, Cornwall and Brockville as these areas are likely to see lighter and less intense snowfall from this system. The same applies to Muskoka and Parry Sound, where 5 to 10 cm is possible.

Lower amounts are expected in the Greater Toronto Area, extending into Hamilton and the Niagara region. Around 2 to 5 cm of snow is expected, mainly during the evening on Monday.

Less than 2 cm is expected for Deep Southwestern Ontario, including Windsor, Chatham and Sarnia, where this system will have very limited impact.

March 14, 2026

Up to 100 cm of Snow Possible as Blockbuster Winter Storm Targets Northern Ontario Starting Sunday With Blizzard Conditions and Ice Storm Risk

March 14, 2026/ Brennen Perry

A powerful and complex storm system is set to impact Ontario beginning Sunday and continuing into early next week. While Southern Ontario will mainly deal with a messy mix of precipitation and rain for much of the event, the situation will be far more serious across parts of Northeastern Ontario, where extremely heavy snowfall, strong winds, and freezing rain could create dangerous travel conditions.

The system will evolve in several phases as it tracks through the region. Snow will initially spread into Northeastern Ontario on Sunday before an influx of warm air begins pushing northward and creating a zone of freezing rain. As the storm gradually moves out of the region on Monday, attention will then turn to the potential for lake effect snow developing late Monday into Tuesday.

Snow will begin spreading into Northeastern Ontario from the southwest during the morning and early afternoon hours on Sunday. At first, the snow may be somewhat light and patchy as the leading edge of the system arrives, but conditions will steadily deteriorate through the afternoon as more intense bands move into the region.

These bands will become particularly strong late Sunday afternoon and evening as the storm reaches peak intensity. Within the heaviest bands, snowfall rates could exceed 5 cm per hour. These intense bursts of snow will quickly overwhelm roads and dramatically reduce visibility.

Strong winds will also play a major role in this storm. Wind gusts of 60 to 90 km/h are expected to develop Sunday afternoon and continue into the overnight hours. When combined with the intense snowfall, these winds will lead to widespread blowing snow and periods of blizzard conditions.

Travel could quickly become extremely hazardous across parts of Northeastern Ontario. Visibility may frequently drop to near zero in the heaviest snow bands and blowing snow. There is a strong likelihood that highways could become impassable at times, and widespread highway closures are possible in the hardest hit regions.

Looking at the snowfall totals, the highest accumulations are expected across parts of central Northeastern Ontario. Areas stretching from Sault Ste. Marie, through Chapleau, Timmins and Kirkland Lake could see between 60 and 100 cm of snow.

Totals will gradually drop off to the north as the core of the system remains farther south. This means communities such as Wawa, Kapuskasing and Cochrane could see between 40 and 60 cm of snow by the time the storm begins to wind down.

Farther south, the story becomes more complicated as ice pellets and freezing rain begin mixing in and reducing snowfall totals. A narrow corridor from Elliot Lake to Temiskaming Shores is currently expected to see between 40 and 60 cm of snow before the changeover occurs.

For areas from Espanola through Sudbury, snowfall totals will likely be closer to 25 to 40 cm. North Bay is expected to see around 10 to 15 cm of snow, most of which will fall during the afternoon on Sunday, before precipitation transitions over to ice pellets and freezing rain.

While snowfall will gradually lighten during the day on Monday across Northeastern Ontario, conditions may still remain difficult in many areas due to deep snow on the ground and lingering blowing snow.

While heavy snow dominates the northern portion of the storm, the next major concern will be the development of freezing rain as warmer air begins pushing northward Sunday evening.

The leading edge of the system will first sweep across Southern Ontario early Sunday, bringing a light mix of wet snow, freezing rain and ice pellets. This initial wave is not expected to produce significant accumulation, but it could still create slippery road conditions during the morning and afternoon as it moves through.

Behind this initial batch of precipitation, much warmer air will surge northward into Southern Ontario through Sunday afternoon and evening. This will transition most areas over to plain rain while the storm continues to produce heavy snow farther north.

As this warm air pushes into the colder air mass across Northeastern Ontario, it will create a corridor favourable for freezing rain. By Sunday evening, a swath of freezing rain is expected to develop, extending from Manitoulin Island through the North Bay region.

Through the late evening and overnight hours, this freezing rain zone is expected to gradually spread northward. Communities, including Elliot Lake and Sudbury, could transition from heavy snow to freezing rain by late Sunday evening.

Within this corridor, freezing rain could become quite significant in some areas, with ice accretion totals potentially reaching 10 to 20 mm. That may lead to power outages and tree damage, especially with the strong wind gusts.

Freezing rain may continue through much of the overnight period and into the morning hours on Monday before temperatures gradually begin to rise.

Across Southern Ontario, the story will shift again on Monday as milder air remains in place for much of the day.

Scattered rain showers and even a few thunderstorms are possible across parts of the region on Monday. However, temperatures may begin to cool later in the day, which could allow precipitation to transition back to snow in some areas.

Exactly how much snow may develop during this transition remains uncertain. A separate detailed forecast will be issued for Southern Ontario once forecast models provide better clarity on how persistent this snow could be and whether meaningful accumulation is likely.

One additional feature we will be watching closely is the potential for lake effect snow developing late Monday into Tuesday.

As colder air moves back into the region behind the storm system, lake effect snow bands could begin forming off Lake Huron and Georgian Bay. These bands may bring an additional 10 to 20 cm of snow to parts of the traditional snowbelt regions, depending on how long they persist.

March 13, 2026

Southern Ontario: School Bus Cancellations and Closures for Friday, March 13, 2026

March 13, 2026/ Alannah Campbell

Please refresh your page every few minutes to receive the latest update

Cancellation & Closure Map (English Public and Catholic Schools)

Please note: School board boundaries are a rough estimate. Don’t use this map to determine what school board or weather zone you live in as accuracy isn’t guaranteed.

Green = No Cancellations
Red = Cancellations (Click for More Details)
Purple = School Closures (Click for More Details)

List of Cancellations & Closures

English Public and Catholic Schools

Avon MaitIand Public & Huron-Perth CathoIic: There are multiple closures/cancellations, please visit this link for more details: https://hpsts.mybusplanner.ca/Alerts
BIuewater Public & Bruce-Grey Catholic: All busses are cancelled.
Simcoe County Public & Simcoe Catholic: All school vehicles in Simcoe County are cancelled today.

French Schools

Conseil catholique MonAvenir: Busses are cancelled in Simcoe
Conseil scolaire catholique Providence: Busses are cancelled in Huron Perth and Bruce-Grey
Conseil scolaire Viamonde: Busses are cancelled in Huron Perth and Bruce-Grey

March 12, 2026

Winter Makes a Comeback Friday with Up to 15cm of Snow Possible Across Southern Ontario

March 12, 2026/ Brennen Perry

While we started off the week with a taste of spring-like weather across Southern Ontario, with widespread double-digit temperatures and even readings soaring near 20°C in some areas, the end of the week will bring us back to reality. And that reality is that winter is far from finished!

An Alberta Clipper is set to slide across the region starting Friday morning and persist throughout much of the day. This system is expected to bring a few hours of heavier snowfall with hourly rates approaching 2 to 3cm through parts of Southwestern Ontario and into the Golden Horseshoe.

That rapid accumulation is expected to occur during the late morning and early afternoon hours, which unfortunately lines up with a very busy time of day. This will set up messy conditions just in time for the afternoon commute, especially on untreated roads and highways.

Drivers should be prepared for rapidly changing conditions with snow quickly covering roads in areas that experience the heavier bursts.

This heavy snow will also be accompanied by strengthening winds with gusts approaching 50 to 70 km/h across many areas. Even stronger gusts are expected around Lake Huron, where some locations could see gusts approaching 80 km/h.

Those strong winds combined with the falling snow will likely create near zero visibility at times on the roads due to blowing snow. In some exposed rural areas, there could even be localized blizzard conditions developing for a time, particularly where open farmland allows the wind to easily pick up and blow the snow around.

Once the system wraps up late Friday into early Saturday morning, most of Southern Ontario will be looking at around 10 to 15cm of fresh snow. That will bring back a familiar winter landscape that was wiped out in many areas thanks to the warm temperatures earlier this week.

The first bands of snow are expected to begin working their way into Southwestern Ontario from the west just after sunrise on Friday morning.

That means locations around Lake Huron will likely be the first to experience the steady snowfall. The snow should start out fairly light early in the morning before gradually increasing in intensity.

For Deep Southwestern Ontario around the Windsor and Chatham area, it looks like they will be sitting right near the freezing mark. These areas could start off with some flurries during the pre-dawn hours, but little accumulation is expected.

As temperatures rise above freezing through the morning hours, precipitation will likely switch over to rain by the late morning, which will limit any snowfall accumulation in this region.

That swath of snow will pick up intensity through the late morning with it spreading eastward into the Greater Toronto Area and regions around Lake Simcoe by around the noon hour. As this occurs, snowfall rates are expected to increase across parts of the region.

It appears that an area of elevated snowfall rates approaching 2 to 3cm per hour could briefly set up in regions east of Lake Huron and into the Golden Horseshoe. Even though this intense snowfall would only last for a few hours, it could still lead to some rapid accumulation in a short period of time.

That burst of heavier snow could lead to some quickly deteriorating road conditions leading up to the afternoon commute and make for some slushy and snow covered roads.

It should be mentioned that temperatures in many of these areas will be sitting very close to the freezing mark. Because of that, it is possible that accumulation may not be as efficient as it would be during colder snowfall events.

Some of the snow may melt as it falls or shortly after reaching the ground, especially on roadways that were warmed by the recent mild weather.

We may even see some mixing along the Lake Erie and Lake Ontario shoreline, especially toward the mid to late afternoon hours when temperatures may briefly creep above freezing.

**wind gusts (km/h)** - MAP FROM WEATHERBELL

Another big factor that will enhance the impact of what would normally be considered a fairly uneventful snowfall event is the wind.

Earlier forecast data suggested much stronger and more widespread wind gusts, but recent model runs have toned those values down somewhat.

Even with that reduction, winds are still expected to be quite gusty with gusts near 50 to 70 km/h across Southwestern Ontario and the Golden Horseshoe. Closer to Lake Huron those gusts could approach 80 km/h at times.

Given the heavier snowfall rates of 2 to 3cm per hour at times, these gusts will likely lead to near zero visibility in some areas with widespread blowing and drifting snow developing.

There could even be some localized blizzard conditions east of Lake Huron, which is particularly vulnerable due to its exposed rural roads and open terrain. In these areas, snow can easily be picked up by the wind and blown across roadways, quickly reducing visibility and creating hazardous driving conditions.

Road closures cannot be ruled out in some of the more exposed locations, especially if blowing snow becomes intense during the peak of the storm.

Heading into the late afternoon hours, the snow will have spread into Central and Eastern Ontario, where it is expected to persist into the evening. Some of the areas further east may not see the snow fully taper off until early Saturday morning as the system gradually exits the region.

It appears that the overall intensity of the snow will slowly decrease by the evening hours, with snowfall rates closer to 1 to 2cm per hour in many areas.

The heaviest pockets during the evening appear to be focused on areas north of Lake Ontario such as York Region, Durham Region, Kawartha Lakes and Peterborough before eventually moving into parts of Eastern Ontario after the dinner hour. Hourly snowfall rates in these areas could still briefly exceed 2cm at times through the evening before gradually easing overnight.

For Southwestern Ontario and the Greater Toronto Area along the Lake Ontario shoreline, rising temperatures near the shoreline will likely lead to a switch from snow to rain by the late afternoon and early evening. This changeover will help limit snowfall totals closer to the lakes.

Another wave of light snow may move in from the west late in the evening and into the overnight hours as colder air flows in behind the departing system. However, this additional snow is not expected to produce significant accumulation.

We are also watching the evening hours closely for Deep Southwestern Ontario, where stronger wind gusts may develop just before midnight.

There is the potential for gusts reaching 80 to 90 km/h for areas such as Windsor, Chatham and Sarnia.

It is even possible that a few isolated severe wind gusts exceeding 90 km/h could occur in localized areas if the strongest winds are able to mix down to the surface.

Overall, we are looking at general snowfall amounts of 10 to 15cm across much of Southern Ontario by Saturday morning.

A few pockets, especially in higher elevation areas like northwest of the Greater Toronto Area and the Dundalk Highlands, could see localized totals approaching 20cm thanks to slightly colder temperatures that will allow snow to accumulate more efficiently.

The 10 to 15cm zone includes Goderich, Kincardine, Owen Sound, Wiarton, Tobermory, Hanover, Orangeville, Kitchener, Guelph, Newmarket, Barrie, Collingwood, Midland, Orillia, Bracebridge, Parry Sound, Huntsville, Peterborough, Bancroft, Pembroke, Renfrew, Smiths Falls and Ottawa.

Slightly lower totals of 5 to 10cm are expected from London into the Niagara region and around the Greater Toronto Area near the Lake Ontario shoreline, continuing east into Kingston and up along the St. Lawrence River.

Temperatures are expected to rise above freezing in this corridor, especially during the afternoon hours, which could reduce the ability for snow to accumulate and even allow some rain to mix in at times.

That includes Grand Bend, London, St. Thomas, Tillsonburg, Niagara Falls, Hamilton, Mississauga, Toronto, Oshawa, Belleville, Picton, Kingston, Brockville and Cornwall.

To the north, lower snowfall totals of 5 to 10cm are also expected in locations such as Algonquin Park, Deep River, North Bay, Sudbury and Elliot Lake. This is mainly because the heavier precipitation bands are expected to stay south of these regions.

Around 2 to 5cm is expected for Sarnia and Chatham as they see rain for much of the event, with less than 2cm likely for the Windsor and Leamington area, where temperatures remain warm enough for precipitation to fall primarily as rain.

March 12, 2026

‘Snow Day’ Forecast: Blowing Snow Threat Friday May Give Some Southern Ontario Students an Early Start to March Break

March 12, 2026/ Brennen Perry

For an updated list of school bus cancellations & school closures, please visit our live article: https://instantweatherinc.com/article/2026/3/13/bus-cancellations

NOTE: Many school boards are off on Friday due to a PA Day. We do not factor PA Days into our forecast because they vary between regions, and even some school boards in the same region can have different PA Days. If you have a PA Day tomorrow, disregard this forecast and enjoy the guaranteed snow day.

Widespread snow is expected to move across Southern Ontario beginning late Friday morning and continuing throughout much of the afternoon and evening. While this will not be a major snowstorm, the combination of steady snowfall and strong wind gusts may create some tricky travel conditions, especially in rural and exposed areas where blowing snow can quickly reduce visibility.

Current projections suggest snowfall totals will generally fall in the 10 to 15 centimetre range by the end of the day in the hardest hit regions. This amount of snow typically sits right near the threshold where school boards begin to consider cancelling buses. However, the biggest complication with this event is the timing.

Unlike snow events that arrive overnight or during the early morning hours, the snow with this system is not expected to begin in most regions until after school transportation decisions have already been made. In many communities, the snow will only just be starting or may not even begin until late morning or early afternoon. That means school boards would need to make proactive decisions based on expected afternoon travel conditions rather than the conditions they see early in the morning.

At this point, Environment Canada has issued a special weather statement for parts of the region rather than a snowfall warning or blowing snow advisory. Historically, many school boards are hesitant to cancel buses proactively when only a special weather statement is in place. That means there is a real possibility that some boards choose to run buses and hope conditions hold off until after the afternoon transportation runs.

If Environment Canada upgrades the alerts to a snowfall warning or blowing snow advisory by Friday morning, the probability of cancellations would increase significantly. Until that happens, the timing and messaging around this event keep the forecast a little more uncertain.

Because of that uncertainty, we have capped our highest probability at 50 percent for the regions most likely to experience poor travel conditions. These are areas that tend to be more rural, have a higher number of exposed routes, and are more vulnerable to blowing snow when winds increase during the afternoon.

The regions that currently sit in this toss-up category include all zones within the Bluewater District School Board, the Avon Maitland District School Board, and Wellington and Dufferin counties under the Upper Grand District School Board. These areas are expected to see some of the more persistent snowfall, along with gusty winds that could produce localized blowing snow. While we are leaning toward at least some cancellations in these regions, the late arrival of the snow keeps confidence from reaching the 75 or 90 percent category.

Beyond these areas, we have placed a wide swath of Southern Ontario in a slight chance category with a 25 percent probability of cancellations. This includes Chatham and Lambton counties under the Lambton Kent District School Board, Middlesex County under the Thames Valley District School Board, the Waterloo Region District School Board, Guelph under the Upper Grand District School Board, all weather zones within the Simcoe County District School Board, South Muskoka along with North and South Kawartha Lakes under the Trillium Lakelands District School Board, Parry Sound under the Near North District School Board, Peterborough and Northumberland counties under the Kawartha Pine Ridge District School Board, and Central Hastings, Belleville, Prince Edward County, Central and South Lennox and Addington, South Frontenac, and Kingston under Tri Board Student Transportation Services.

These areas may also see periods of blowing snow and reduced visibility through the day on Friday. However, we are leaning toward many of these school boards choosing to operate buses as normal because the snow will not arrive until later in the day for many of these regions. In Central and Eastern Ontario, especially, some boards may decide to roll the dice and hope the worst conditions develop after the afternoon bus run.

In Southwestern Ontario, the lower probability is due in part to some of these regions being more urban, such as Waterloo Region and Guelph, where the threshold for cancellations is typically higher. In other areas, the special weather statement does not specifically mention blowing snow, even though localized blowing snow is still possible with gusty winds.

Across the remainder of Southern Ontario, including northern portions of Central and Eastern Ontario and the Greater Toronto Area, a snow day on Friday appears unlikely. For the urban school boards around the Greater Toronto Area, the expected snowfall amounts are well below the threshold that usually prompts cancellations. Meanwhile, regions farther north and east are expected to see lighter totals overall, with the bulk of the snowfall occurring later Friday afternoon and evening, after the school day is already over.

This forecast comes with a higher-than-normal amount of uncertainty because of the timing of the snow. Many may look at snowfall totals of 10 to 15cm and expect a higher likelihood of cancellations. However, because most of the snow is expected after the morning decision window, the probability of cancellations is slightly lower than it might otherwise be.

Even so, a 25 percent or 50 percent chance is still notable and indicates that at least some regions could see buses cancelled depending on the proactivity of each school board or bus company.

Disclaimer: Instant Weather has zero authority when it comes to bus and school closures.

It is completely up to the school boards, bus companies, local authorities, and parents to decide what is best for their children. This is our best guess based on our forecast.

March 12, 2026

Southern Ontario: School Bus Cancellations and Closures for Thursday, March 12, 2026

March 12, 2026/ Alannah Campbell

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Cancellation & Closure Map (English Public and Catholic Schools)

Please note: School board boundaries are a rough estimate. Don’t use this map to determine what school board or weather zone you live in as accuracy isn’t guaranteed.

Green = No Cancellations
Red = Cancellations (Click for More Details)
Purple = School Closures (Click for More Details)

List of Cancellations & Closures

English Public and Catholic Schools

Near North Public & Nipissing-Parry Sound CathoIic: School bussing is cancelled in the following Weather Zones: West Nipissing, Trout Lake/Four Mile Lake, Redbridge/Thorne, Highway 11 North, East Parry Sound North, East Parry Sound South, North Bay, Mattawa, and Callander/Bonfield/East Ferris.
Tri-Board: Coe Hill and Maynooth schools are closed due to power outages.

French Schools

Le Conseil scolaire public du Nord-Est de l’Ontario (CSPNE) & Conseil scolaire catholique Franco-Nord: School bussing is cancelled in the following Weather Zones: West Nipissing, Trout Lake/Four Mile Lake, Redbridge/Thorne, Highway 11 North, East Parry Sound North, East Parry Sound South, North Bay, Mattawa, and Callander/Bonfield/East Ferris.

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