BREAKING: Major Winter Storm Expected for Ontario Beginning Sunday with Blizzard Conditions, Up to 50cm of Snow, 70-100km/h Winds, Flash Freezing, and 10-20mm of Freezing Rain

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Environment Canada has upgraded their forecast map for this major winter storm expected to affect Ontario late Sunday through Monday. In their forecast, they’re mentioning a high risk for blizzard conditions, 70-100km/h wind gusts, 15-50cm of snow, intense snow squalls, 10-20mm of freezing rain and a flash freeze for parts of northeastern and southern Ontario.

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Sunday, December 28th:

The storm begins on Sunday for many and really begins to ramp up Sunday evening and overnight. Below is Environment Canada’s location specific details:

”Location A: Portions of northeastern, eastern and central Ontario. Parts of the Greater Golden Horseshoe.

Hazard(s): Ice

Timing: Afternoon and evening into Monday.

Impact(s): Icy surfaces such as roads and walkways.

Impact level: High (3/4)
Confidence level: Moderate (2/4)

A long-duration freezing rain event is expected to begin in the afternoon, and evening for eastern Ontario. The event remains uncertain in terms of the areas that will receive the highest amount of freezing rain. Confidence is highest over areas of higher terrain and central Ontario.

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Location B: Parts of southwestern Ontario and the Golden Horseshoe.

Hazard(s): Ice, Rain

Timing: Afternoon through evening.

Impact(s): Possible difficult travel conditions. Flooding in low-lying areas including roads.

Impact level: Low (1/4)
Confidence level: Moderate (2/4)

Freezing rain is possible with the approach of a low pressure system. Freezing rain is expected to be brief for most areas before a transition to rain, where up to 40 mm is possible through Monday morning.

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Location C: Parts of northeastern Ontario.

Hazard(s): Ice

Timing: Early morning.

Impact(s): Possible difficult travel conditions.

Impact level: Moderate (2/4)
Confidence level: Low (1/4)

Patchy areas of freezing rain and ice pellets are possible.

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Location D: Parts of southwestern Ontario and the Niagara Peninsula.

Hazard(s): Rain, Thunderstorm

Timing: Morning through Monday.

Impact(s): Flash flooding and water pooling on roads.

Impact level: Low (1/4)
Confidence level: Moderate (2/4)

Rainfall ahead of a low pressure system could bring amounts of 20 to 40 mm. Thunderstorms are also possible in the evening into Monday morning. Locally higher rainfall totals up to 50 mm are possible under heavier showers or thunderstorms.

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Location E: Parts of northeastern Ontario.

Hazard(s): Ice

Timing: Late afternoon or evening into Monday.

Impact(s): Possible difficult travel conditions.

Impact level: Moderate (2/4)
Confidence level: Low (1/4)

Freezing rain is possible with the approach of a low pressure system. Ice pellets are likely to mix in as well.”

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Monday, December 29th:

Here’s Environment Canada’s details for Monday:

”Location A: Eastern and central Ontario.

Hazard(s): Ice, Rain, Wind

Timing: Ending in the morning or early afternoon.

Impact(s): Icy surfaces such as roads and walkways. Broken tree branches from ice build-up. Utility outages.

Impact level: High (3/4)
Confidence level: High (3/4)

A strong and deep low will track across the area. A significant, prolonged freezing rain event is expected to continue into the morning or early afternoon. Lesser ice accretion is expected for areas just east of Georgian Bay and north of Lake Ontario. Wind gusts up to 60 km/h in the wake of the system may be impactful to areas with ice build-up. After temperatures rise above zero, up to 20 mm of rain is also possible.

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Location B: Portions of northeastern and central Ontario.

Hazard(s): Snow, Blowing snow, Ice

Timing: Beginning in the morning.

Impact(s): Difficult travel conditions, reduced visibility and possible road closures. Icy surfaces such as roads and walkways.

Impact level: High (3/4)
Confidence level: Low (1/4)

With a deep low moving across the region, snowfall of 10 to 20 cm and blowing snow are possible. Ice pellets are likely to mix in for much of the region, reducing total snowfall accumulations. Freezing rain is also possible for regions south of Sudbury including Manitoulin Island.

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Locations C: Southeast of Georgian Bay, and northeastern shores of Lake Ontario and Lake Erie.

Hazard(s): Wind, Blowing snow, Snow, Ice

Timing: Beginning in the morning.

Impact(s): Loose objects may be tossed. Possible power outages. Difficult travel conditions, reduced visibility and possible road closures.

Impact level: Moderate (2/4)
Confidence level: High (3/4)

Strong westerly or northwesterly wind gusts of up to 100 km/h are possible in the wake of the strong low pressure system. Brief bands of heavy snow and local blowing snow are likely to accompany the strong winds by Monday afternoon. Snow squalls are expected to develop off of Georgian Bay in the evening and continue through Tuesday. Icy surfaces are also possible with temperatures quickly falling to below zero in the morning.

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Locations D: Portions of northeastern Ontario from Chapleau to Timmins.

Hazard(s): Snow, Blowing snow

Timing: Beginning early morning.

Impact(s): Hazardous travel conditions, reduced visibility and road closures. Snow covered and slippery surfaces such as roads and walkways.

Impact level: High (3/4)
Confidence level: High (3/4)

With a deep low moving across the region, heavy snowfall up to 50 cm and blowing snow are possible, with local blizzard conditions possible especially for regions closer to Lake Superior. Travel on Highway 11 will likely be disrupted. The snow is expected to gradually taper to flurries Monday overnight or Tuesday morning, while the moderate to strong winds and local blowing snow are expected to continue through Tuesday afternoon.

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Location E: Portions of northeastern Ontario east of Lake Superior.

Hazard(s): Snow, Wind, Blowing snow

Timing: Beginning early morning.

Impact(s): Possible power outages. Dangerous travel conditions, reduced visibility and road closures. Snow covered and slippery surfaces such as roads and walkways.

Impact level: High (3/4)
Confidence level: High (3/4)

With a deep low moving across the region, heavy snowfall up to 40 cm and blizzard conditions are possible with strong wind gusts of up to 90 km/h. Travel on highway 17 will likely be disrupted. The snow is expected to gradually taper Monday evening while the strong winds and blowing snow conditions are expected to improve later Monday night.

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Locations F: Portions of northeastern Ontario from Marathon to Little Abitibi

Hazard(s): Snow, Blowing snow

Timing: Beginning Sunday night.

Impact(s): Difficult travel conditions, reduced visibility and possible road closures. Snow covered and slippery surfaces such as roads and walkways.

Impact level: Moderate (2/4)
Confidence level: High (3/4)

Heavy snowfall up to 15 cm and local blowing snow are possible. Conditions are expected to be the poorest near Lake Superior.

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Location G: Southeast of Lake Huron.

Hazard(s): Wind, Blowing snow, Snow, Ice

Timing: Beginning in the morning.

Impact(s): Dangerous travel conditions, reduced visibility and road closures. Possible power outages. Icy surfaces such as roads and walkways.

Impact level: Extreme (4/4)
Confidence level: High (3/4)

Blizzard conditions in snow squalls are possible with strong wind gusts of up to 100 km/h in the wake of the strong low pressure system. Near zero visibility and bursts of heavy snow are likely especially in the afternoon. Icy surfaces are also possible with temperatures quickly falling to below zero early in the morning.

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Location H: Portions of southwestern and central Ontario, as well as the Golden Horseshoe.

Hazard(s): Ice, Wind, Blowing snow

Timing: Beginning in the morning.

Impact(s): Loose objects may be tossed. Possible reduced visibility. Icy surfaces such as roads and walkways.

Impact level: Moderate (2/4)
Confidence level: Moderate (2/4)

Icy surfaces are possible with temperatures quickly falling to below zero in the morning. Strong wind gusts up to 70 km/h are possible through the day. Local blowing snow may accompany these wind gusts, especially over southwestern Ontario.”

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ZOOMED VERSION OF MONDAY FORECAST TO SHOW MORE LOCATIONS IN SOUTHERN ONTARIO - NOTE: CLICK OR TAP THE IMAGE TO OPEN AN IMAGE YOU CAN ZOOM

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Tuesday, December 30th:

ENVIRONMENT CANADA’s FORECAST MAP FOR TUESDAY, DECEMBER 30th, 2025 - NOTE: CLICK OR TAP THE IMAGE TO OPEN AN IMAGE YOU CAN ZOOM

And, of course, no winter storm would be complete without snow squalls the next day. Environment Canada expecting snow squalls for London, Goderich, Barrie, Newmarket, Collingwood, Wasaga Beach, Stayner, Angus and surrounding communities on Tuesday. 10-20cm possible with gusty winds creating blowing snow and possible whiteouts. Specifically in the squalls east of Lake Huron, 70km/h wind gusts are possible as per Environment Canada:

”Locations A and B: Areas southeast of Lake Huron and Georgian Bay.

Hazard(s): Snow, Blowing snow, Wind.

Timing: Tuesday.

Impact(s): Difficult travel conditions, reduced visibility and possible road closures.

Impact level: High (3/4)
Confidence level: Moderate (2/4)

In the wake of the low pressure system, snow squalls are likely to set up off Lake Huron and Georgian Bay with snowfall up to 20 cm, local blowing snow, and strong wind gusts of up to 70 km/h.”

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In summary:

It’s looking likely at this point that Sunday into Monday will be a major winter storm with significant impacts to travel, power outages, icy conditions, significant snowfall, whiteouts, and intense, potentially damaging wind gusts. If you don’t have to travel during this storm, that would be best. However, if it’s an emergency or you’re on the front lines, please give yourself as much time as possible. More details ASAP.

Boxing Day Winter Storm Poised to Deliver Ice Storm Risk and Heavy Snow to Southern Ontario on Friday

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With Christmas now behind us, the focus turns to the final stretch of 2025 as we approach New Year’s next Thursday. And it’s looking like the last seven days of the year will be anything but quiet when it comes to the weather across Southern Ontario.

That active pattern becomes clear very quickly with a looming Boxing Day winter storm expected to bring a messy mix of precipitation. Some areas will see periods of heavy snowfall, while others could be dealing with a potentially damaging ice storm with prolonged freezing rain through much of the day.

For much of Central Ontario, along with parts of the Golden Horseshoe and into portions of Southeastern Ontario, the primary concern will be snowfall. Widespread totals in the 10 to 20 cm range are possible by the end of Friday. The Ottawa Valley is expected to remain on the lower end, generally staying under the 10 cm mark.

The forecast becomes more complicated through Southwestern Ontario, extending through Hamilton and into the Niagara Region. Here, a mix of snow and ice pellets is expected, which will limit snowfall totals but still create hazardous travel conditions.

The freezing rain risk has shifted slightly northward in the latest model guidance, as warmer air aloft is now expected to push deeper into Southern Ontario than earlier projections suggested. This places the Sarnia to London corridor in the bullseye for the highest ice accretion. Freezing rain totals of 10 to 15 mm are possible, which could result in significant power outages and very icy road conditions.

Beyond Friday, attention is already turning to another slow-moving system expected to arrive Sunday and linger into Monday. This system appears to have access to much more moisture compared to Friday’s storm, raising the concern for a prolonged period of freezing rain that could last anywhere from 12 to 24 hours.

What adds to the concern is that current model guidance is focusing this next threat over parts of Central and Eastern Ontario, the same areas that were hardest hit by last winter’s major ice storm. There is still uncertainty with the exact track, and it could shift north or south, but it is something we are watching very closely.

PRECIP TYPE - MAP FROM WEATHERBELL

Before we get ahead of ourselves, the immediate focus remains on Friday’s storm. Precipitation is expected to begin during the early to mid-morning hours as bands move in from the west. Light to moderate snow will spread into Grey-Bruce, Simcoe County, Muskoka and the GTA during this time.

For Windsor, Chatham and Sarnia, light freezing rain is expected to begin by mid-morning. Precipitation may be somewhat scattered at first but will steadily increase in coverage and intensity as the morning progresses.

PRECIP TYPE - MAP FROM WEATHERBELL

By late morning, the worst conditions should be underway, with heavy icing ongoing around Chatham, Sarnia and London. Travel conditions in these areas are expected to deteriorate quickly.

Further north and east, heavy snow will be the main concern across Muskoka, Simcoe County, Peterborough and the eastern GTA, including the City of Toronto.

Between the freezing rain to the southwest and the heavy snow to the north and east, a corridor of ice pellets is expected to develop from the Lake Huron shoreline through Kitchener and into Hamilton.

PRECIP TYPE - MAP FROM WEATHERBELL

Poor conditions will persist into Friday afternoon, with steady snowfall continuing across Central Ontario into Kingston. Wind gusts approaching 40 km/h may lead to localized blowing snow, further reducing visibility at times.

The ice pellet zone may also push further into the GTA, with Toronto potentially switching over to ice pellets for a time. This would limit snowfall totals and keep them closer to the 10 cm range.

Sarnia and London are expected to remain locked into freezing rain through much of the afternoon. There may be some hope for the Chatham area, where temperatures could briefly rise just above freezing and allow a changeover to rain by mid-afternoon. However, this is right on the line and could still go either way. Windsor and Leamington are expected to remain solidly in the rain zone.

PRECIP TYPE - MAP FROM WEATHERBELL

The system is expected to gradually wind down later Friday afternoon and into the early evening. Precipitation will taper off first across western areas, then slowly come to an end across the Golden Horseshoe and Eastern Ontario by late evening.

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Based on the latest data, the highest ice storm concern has been focused on the Sarnia, Lambton, Middlesex and London corridor. While there is still some disagreement on exact intensity, the potential exists for ice accretion exceeding 10 mm, with localized amounts approaching 15 mm.

Communities included in this higher risk zone include Wallaceburg, Sarnia, Petrolia, Thamesville, Lambton Shores, Grand Bend, St. Thomas and London.

Across Essex County, the highest ice accretion is expected in the northern portions of the county, including Windsor and Tilbury. These areas could see 5 to 10 mm of ice before a changeover to rain. Closer to the Lake Erie shoreline, including Leamington, icing should be minimal, generally under 2 mm, as temperatures rise above freezing more quickly.

Further north, freezing rain amounts will be reduced as ice pellets dominate initially, with freezing rain gradually mixing in later. Locations such as Lucan, Exeter, Woodstock, Tillsonburg, Simcoe, Port Colborne and Fort Erie could see a faster transition to freezing rain, with 5 to 10 mm of ice possible following a few hours of ice pellets.

For Huron and Perth counties, including Kitchener, Brantford and Niagara Falls, ice pellets are expected to linger longer. This will limit freezing rain to only a few hours near the end of the storm, with ice accretion generally in the 2 to 5 mm range. Less than 2 mm of icing is expected for Hamilton, Guelph and southern Grey-Bruce.

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On the snowfall side of the storm, the highest totals are expected to range from 10 to 20 cm across Northeastern Ontario, down into Central Ontario and parts of Eastern Ontario.

This includes areas such as Sudbury, North Bay, Parry Sound, Muskoka, Simcoe County, York Region, Toronto, Durham Region, the Kawarthas, Peterborough and Kingston.

Lower snowfall totals are expected in the Ottawa Valley, where amounts of 2 to 5 cm are forecast for Ottawa and 5 to 10 cm from Bancroft into Brockville. This is due to the core of the system’s moisture remaining further south.

South of the heaviest snow band, totals will decrease as ice pellets mix in later in the storm. Grey-Bruce, Orangeville, Guelph and the western GTA are currently expected to see 5 to 10 cm, though some model solutions suggest even less if mixing becomes more dominant.

Even lower snowfall totals are expected east of Lake Huron into Hamilton and Niagara, where less than 5 cm is forecast as ice pellets and freezing rain become the primary precipitation types.

PRECIP TYPE - MAP FROM WEATHERBELL

Once this system exits Friday night, Saturday should bring a brief period of calmer weather. However, that break will be short-lived, as another potentially high-impact winter storm is expected to approach as early as Sunday, possibly arriving in multiple waves.

The overall setup supports the potential for a prolonged area of freezing rain that could remain locked in place into Monday. This raises concern for a significant ice storm event, potentially similar in nature to last winter’s devastating storm across Central and Eastern Ontario.

Those same regions are once again in the early bullseye. While there is still time for this forecast to change, this is the type of setup where residents should begin thinking ahead and preparing for the possibility of extended power outages if the scenario does not improve.

We will continue to monitor this closely and will have a more detailed update once we get through Friday’s storm.

BREAKING: Environment Canada Forecasting Possible Significant Freezing Rain for Parts of Ontario

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Environment Canada is monitoring a deep low-pressure system expected to affect Ontario late Sunday through Monday. While details remain uncertain this early on, a “significant, prolonged period of freezing rain event” is possible as per Environment Canada’s meteorologists. In addition to the freezing rain, heavy snow, and strong winds are possible in parts of the province. Surfaces like roads, sidewalks, and trees may become dangerously icy, and widespread power outages are possible if this continues to trend strong.

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Sunday, December 28th:

Location A (Ice, 3mm): A potential freezing rain event could glaze roads and walkways across eastern and central Ontario and parts of the Greater Golden Horseshoe. Confidence remains low regarding exact timing, precipitation type, and coverage.

Location B (Snow, 5–10cm): Northeastern Ontario may see 5 to 10 cm of snow, leading to difficult travel conditions and reduced visibility. Snowfall amounts and affected areas remain uncertain this early on.

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Monday, December 29th:

Location A (Ice, 10mm+): A strong and deep low could produce significant, prolonged freezing rain across eastern and central Ontario, with ice accretion on trees and power lines leading to branch breakage and power outages.

Location B (Snow & Blowing Snow, 15–20 cm): Portions of northeastern and central Ontario may receive 15–20 cm of snow with blowing snow and gusts up to 70 km/h, causing difficult travel and reduced visibility.

Locations C & D (Wind, 70–90 km/h): Westerly or northwesterly wind gusts of 70–90 km/h are possible along the eastern shores of Lake Huron, northeastern shores of Lake Ontario, and Lake Erie, potentially tossing loose objects and causing power outages.

Location E (Ice & Wind, 10 mm & 80 km/h): Southeast of Georgian Bay may experience a combination of prolonged freezing rain and wind gusts up to 80–90 km/h, resulting in ice build-up and possible significant impacts. Confidence remains moderate to low for precipitation type, amounts, and exact areas but we’ll continue to monitor this carefully over the next few days to see how it progresses.

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In summary:

The exact details of this event continue to unfold and there is potential for this to change. However, there is quite a bit of agreement on the models at this time regarding the prolonged freezing event with strong wind gusts. Please be prepared for slippery roads, reduced visibility and potential power outages and now would be a good time to begin reviewing your travel plans if you plan to travel on Sunday or Monday. More details ASAP.

Potential Boxing Day Winter Storm Targets Southern Ontario With Significant Freezing Rain Risk and Up to 15-20cm of Snow

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While winter weather has mostly taken a breather across Southern Ontario over the past week, things are about to turn active again as we head into the final days of 2025.

That change begins on Boxing Day with a messy winter system expected to slide through Southern Ontario. This system will bring a wide range of hazards, including the threat of significant freezing rain in Deep Southwestern Ontario and more widespread snowfall across much of the rest of the region.

There are still some question marks surrounding this storm, particularly when it comes to how strong it ultimately becomes. Some lower-resolution models show a fairly robust system with plenty of moisture to work with. At the same time, higher resolution guidance that is now coming into range is hinting at some drier pockets, which could cause this system to underperform in spots.

Complicating matters further is the fact that this system has the characteristics of an Alberta Clipper. Clippers are notorious for being difficult to forecast since they often lack a deep source of moisture, and small changes can make a big difference in precipitation type and totals.

What we do know at this point is that impacts will vary significantly across Southern Ontario. The highest risk area continues to be Deep Southwestern Ontario, especially the Windsor, Chatham and Sarnia region, which currently sits in the bullseye for prolonged freezing rain.

In these areas, sustained freezing rain could lead to substantial ice accretion on roads, trees and power lines. This would result in dangerous travel conditions and an increased risk of power outages. With over 10mm of icing possible, there is also concern for widespread tree damage as branches struggle under the weight of the ice.

Further north, from areas east of Lake Huron through the Greater Toronto Area and into Central and Eastern Ontario, the primary precipitation type is expected to be snow. Snow will fall steadily through much of the day on Friday with general accumulations of 5 to 15cm by the end of the day. Locally higher amounts approaching 20cm are possible west of Lake Ontario around the Toronto area due to lake enhancement.

PRECIP TYPE - MAP FROM WEATHERBELL

The first bands of precipitation are expected to arrive early to mid-morning on Friday, spreading across Lake Huron into Southwestern Ontario. As the system moves in, it will encounter a stubborn layer of cold air near the surface across Deep Southwestern Ontario, including Windsor, Leamington, Chatham and Sarnia.

At the same time, warmer air will surge in above the surface, creating a classic setup for freezing rain. This warm layer aloft melts the snow into rain, which then freezes on contact with cold surfaces at the ground.

850MB TEMPS (1.5KM ABOVE GROUND) - MAP FROM WEATHERBELL

The biggest challenge with events like this is determining how far north and how deep that warm layer extends. This is the key factor that decides whether precipitation falls as ice pellets or as freezing rain.

Temperatures roughly 1.5km above the surface vary considerably between models. The Canadian model is more aggressive, pushing the warm layer farther north into Southwestern Ontario and even as far as London.

Overall, model consensus places the freezing line somewhere near a Sarnia to London corridor. Areas south of this line are more likely to see freezing rain, while areas to the north will see a mix of ice pellets and snow.

PRECIP TYPE - MAP FROM WEATHERBELL

By the early afternoon, heavier snow will begin spreading into Central Ontario and the Golden Horseshoe as precipitation from Northern Ontario moves southeast across Georgian Bay. At the same time, freezing rain will be ongoing around Windsor, Chatham and Sarnia.

There are indications that temperatures may slowly climb above freezing for southern Essex County, including Leamington and eventually Windsor. There is still disagreement on the exact timing of this changeover, but it appears most likely sometime during the early to mid-afternoon.

If temperatures do rise above freezing, freezing rain would switch to plain rain, and any ice accretion would begin to melt. How quickly this happens will be critical in determining overall impacts. If the warmup is delayed until later in the day or temperatures stubbornly remain below freezing before dropping Friday night again, impacts could be significantly worse.

For areas like Chatham-Kent, Sarnia and St. Thomas, there is growing concern that temperatures may remain below freezing for much of the event. This would allow ice to accumulate for a prolonged period, with over 10mm of accretion possible. Ice amounts of this magnitude are capable of bringing down tree limbs and power lines, potentially leading to power outages that could last for several days.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

By mid-afternoon, the heaviest snow will be pushing through the Golden Horseshoe. Some models are showing the potential for lake enhancement along the Lake Ontario shoreline from Niagara through Hamilton and into Toronto. If this develops, snowfall rates could briefly spike to 3 to 5cm per hour compared to the more general 1 to 2cm per hour elsewhere.

It is also important to note that ice pellets may mix in at times, which can limit snowfall totals since ice pellets are denser than snow. This is most likely for areas such as London, Kitchener, Hamilton and Niagara, where conditions are more supportive of mixed precipitation. Areas closer to Toronto and farther north into Central Ontario should see more consistent snow.

Light to moderate snow will also spread into Eastern Ontario by the afternoon and continue into the evening before tapering off around midnight. Confidence in snowfall totals here is lower, but amounts in the 5 to 10cm range appear possible by the end of the day.

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While there is decent agreement on the overall track of this system, fluctuations are still very likely. Freezing rain events are among the most difficult to forecast, and even small temperature changes can have major impacts.

At this time, the highest confidence for the worst impacts remains across the Chatham, Windsor and St. Thomas area, where a persistent band of freezing rain is expected to set up for much of the day on Friday. Some models show up to 20mm of liquid precipitation, though not all of that would freeze on surfaces. For now, we are forecasting over 10mm of ice accretion, with the understanding that an overachieving scenario is still on the table.

For southern Essex County, including Leamington and possibly southern Windsor, ice accretion of 5 to 10mm is possible before a changeover to rain. Because of this transition, overall impacts should be lower compared to areas farther north, where freezing rain may last longer.

Farther north, from Sarnia through London and into Norfolk County, precipitation may begin as ice pellets in the morning before transitioning to freezing rain later in the afternoon or early evening. Ice accretion here could range from 3 to 8mm, depending on how quickly this transition occurs.

A corridor stretching from Goderich through Kitchener, Hamilton and into the Niagara region is expected to start with heavier snow Friday afternoon. Mixing with ice pellets later in the day could reduce snowfall totals, with most areas seeing around 5 to 10cm by the end of the event.

Areas that remain predominantly snow from start to finish include Grey-Bruce, much of Central Ontario, Eastern Ontario and the eastern portions of the GTA. Snowfall totals here should generally range from 10 to 15cm, with localized amounts up to 20cm. In Eastern Ontario, especially closer to the Quebec border, totals may struggle to reach 10cm, making 5 to 10cm a more realistic expectation.

We will continue to monitor the latest data closely and will have a more detailed and refined forecast on Thursday night. That update will provide a clearer breakdown of precipitation types and expected amounts. Be sure to check back for the final forecast.

White Christmas Locked In for Parts of Southern Ontario, While Others Face the Risk of a Green Christmas for 2025

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As the big day approaches this Thursday, many across Southern Ontario are starting to ask the big question. Will we wake up to that picture-perfect White Christmas, or will the Grinch sneak in at the last minute and snatch it away from right under our noses (and our carrots)?

In some parts of Southern Ontario, especially the snowbelt regions, it might feel like a White Christmas is already wrapped up and sitting under the tree. These areas were absolutely pummelled by relentless snow squalls earlier this month, leaving behind an impressive snowpack.

But for others, it has been a very different story. Some regions managed to dodge the worst of the snow so far this season, and whatever snow did fall has largely melted away thanks to a recent stretch of milder weather.

That sets the stage for a classic Christmas weather showdown. The Grinch, helped along by a few Heat Miser inspired temperature spikes, will try to erase what little snow remains. Jack Frost, however, is waiting in the wings and is expected to take over closer to Christmas. This makes a weak system expected Tuesday into Wednesday the key player, potentially delivering a last minute chance at a White Christmas for some areas.

CURRENT SNOWFALL DEPTH (cm) - MAP FROM WEATHERBELL

We begin by looking at the existing snowpack, which is often the biggest clue in determining where a White Christmas is all but guaranteed. The most impressive snowpack is found east of Georgian Bay through Simcoe County and into Muskoka, Haliburton and Bancroft.

Model estimates suggest a solid 10 to 25cm of snow on the ground here. These models are fairly low resolution and likely underestimate reality, especially since much of this snow fell during intense lake effect events.

There is also a respectable snowpack of around 5 to 15cm in the higher elevations of Southwestern Ontario, particularly northeast of London. These areas have taken the brunt of snow squall activity several times already this month. Meanwhile, snowpack east of Lake Huron has been noticeably reduced by the recent mild spell.

Outside of those regions, there really is not much snowpack left that can meaningfully contribute to a White Christmas. This includes Deep Southwestern Ontario, the Niagara Region, much of the Golden Horseshoe and into Eastern Ontario, including the Ottawa Valley.

estimated max temp on tuesday - MAP FROM WEATHERBELL

The first challenge arrives early this week as temperatures steadily rise above freezing for more than 24 hours. The warmest day looks to be Tuesday, with daytime highs climbing above freezing across much of Southern Ontario, with the main exception being parts of the Ottawa Valley.

Some areas could even push into the mid to upper single digits, especially in Deep Southwestern Ontario and around the Golden Horseshoe. That is more than enough warmth to put a serious dent in any remaining snow.

Rain may also enter the picture early Tuesday in some areas. Combined with above-freezing temperatures, this will further erode minor snowpack. At that point, the only snow that is truly expected to survive is east of Georgian Bay. For many other areas, including east of Lake Huron, the final outcome will depend heavily on the last 36 hours leading up to Christmas morning.

NEW SNOWFALL BY CHRISTMAS MORNING (cm) - MAP FROM WEATHERBELL

The system moving through on Tuesday is expected to bring light snowfall across Eastern Ontario. With temperatures expected to remain below freezing afterward, this snowfall should help lock in a White Christmas for the Ottawa area, even though there is currently very little snow on the ground. A general 5 to 10cm by Wednesday should be more than enough to tip the scales.

In Southwestern Ontario, however, the outlook is not as festive. Much of the snowfall associated with this system is expected to fall before temperatures rise and precipitation transitions to rain. Any snow that does fall will likely melt away quickly.

The one exception may be the higher elevations east of Lake Huron, where temperatures could hover near freezing just long enough for the snowpack to cling on until Christmas morning. Even there, it will be very close.

estimated temp on CHRISTMAS MORNING - MAP FROM WEATHERBELL

By Christmas morning itself, current indications suggest many across Southern Ontario will wake up to below freezing temperatures. That will help preserve whatever snow remains on the ground. This includes much of Central and Eastern Ontario, as well as higher elevations northwest of the GTA, such as Orangeville and Kitchener.

In Deep Southwestern Ontario and areas along the Lake Erie shoreline into parts of the GTA, temperatures are expected to be slightly above freezing. With very little existing snowpack to work with, those milder conditions are likely to melt away any lingering hope of a White Christmas.

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Putting all of this together, we have created our preliminary White Christmas forecast. This is not the final word and adjustments are possible as we get closer to Christmas morning. Several of the uncertainties mentioned above will resolve themselves over the next couple of days, giving us a clearer picture than the models can provide right now.

Our highest confidence area, where we can almost guarantee a White Christmas with a 90 percent chance, covers a wide swath of Central Ontario, including Muskoka, Bancroft and northern and western Simcoe County. These regions have a deep, well-established snowpack. East of Lake Huron, we also assign a 90 percent chance for Hanover and much of Huron and Perth Counties, where repeated lake effect snow has buried the landscape.

Outside of that core region, we currently have a 75 percent chance for much of Eastern Ontario, along with areas such as Peterborough, Barrie and Kitchener. Confidence is fairly strong here, thanks to the existing snow southeast of Georgian Bay and the expected system snowfall in Eastern Ontario on Tuesday.

That said, melting remains a concern for Barrie and Kitchener if temperatures rise a bit more than expected on Tuesday. For Eastern Ontario, confidence also depends on the system delivering as forecast, so we want to see that snow on the ground before bumping probabilities any higher.

Closer to Lake Ontario, the dream of a winter wonderland starts to fade. From Kingston through the north GTA corridor and extending into London, we currently place the odds at around 50 percent. Along the immediate Lake Ontario shoreline, including much of the GTA, things become even more questionable with only about a 25 percent chance of a White Christmas.

For those in the Niagara Region and Deep Southwestern Ontario, including Windsor, Chatham and Sarnia, it may take a true Christmas miracle. Unless a last-minute snowmaker slides through just before Christmas morning, it looks like the Grinch may win this one.

We will continue to monitor the forecast closely and provide updates as Christmas morning draws nearer. Keep checking back, because in the weather, especially at Christmas, surprises are always possible.

Ontario: Environment Canada Forecasting Snow, Strong Winds, Cold, and Possible Freezing Rain Risk This Week

Environment Canada meteorologists are forecasting the potential for accumulating snow, strong wind gusts, and significant cold for parts of Ontario on Tuesday. Additionally, they’re mentioning the potential for a fairly widespread freezing rain event on Friday. However, confidence is low regarding Friday at this point.

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Tuesday, December 23rd, 2025

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Location A: Fort Severn in Northwestern Ontario

Hazard: Cold (-40c to -45c wind chill)

Timing: Monday night into Tuesday morning

Impact(s): Risk of hypothermia and frostbite if outside for long periods without adequate protection.

Impact level: Moderate (2/4)

Confidence Level: High (3/4)

“Cold wind chill values between -40 and -45 are expected.”

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Location B: Portions of northeastern, eastern, and central Ontario

Hazard: Snow (5-10cm)

Timing: Tuesday morning into the evening

Impact level: Moderate (2/4)

Confidence Level: Low (1/4)

“Snowfall amounts of 5 to 10 cm are possible. At this time, the track and timing of

the low passing through the area are still uncertain.

Possible difficult travel conditions. Snow covered and slippery surfaces such as roads and walkways.”

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Location C: Areas east of Lake Superior, Lake Huron, and Georgian Bay

Hazard: Wind

Timing: Tuesday afternoon into the evening

Impact(s): Loose objects may be tossed

Impact level: Moderate (2/4)

Confidence Level: Moderate (2/4)

“Strong winds from the northwest gusting up to 80 km/h are possible.”

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Friday, December 26th, 2025

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Location A: Portions of northeastern and southern Ontario

Hazard: Ice

Timing: Friday

Impact(s): Possible icy surfaces such as roads and walkways. Broken tree branches from ice build-up.

“A low pressure system is expected to bring an area of freezing rain to portions of northeastern and southern Ontario. There may be 5 to 10 mm of ice accretion in areas affected by the main freezing rain band. However at this time, the track and timing of the low pressure system is quite uncertain.

Confidence is too low in the extended range to assign a weather threat level above minor. Impacts may reach moderate or greater. Watch for future updates.”

The exact track and timing of the low pressure system remain quite uncertain, meaning the freezing rain threat zone may shift in future forecasts.

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In Summary

Snow and strong winds will impact much of southern, eastern, and central Ontario on Tuesday, with snowfall totals of 5-10 cm possible and winds gusts possibly reaching 70-80 km/h near Lake Huron and Georgian Bay.

Far northwestern Ontario will experience significant cold temperatures, with wind chills between -40c and -45c near Hudson Bay.

Friday brings an increasing risk of freezing rain across parts of south, eastern, and central Ontario, along with northeastern Ontario 5-10 mm of ice accretion will be possible. However, the forecast confidence remains fairly uncertain at this time as we’re several days away.

More details ASAP!

Southern Ontario: School Bus Cancellations and Closures for Friday, December 19, 2025

**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 several closures/cancellations, please visit this link for more details: https://hpsts.mybusplanner.ca/Alerts

• BIuewater Public & Bruce-Grey Catholic: All busses are cancelled.

• Dufferin-PeeI Catholic: Buses to St. Andrew, St. Peter, St. Benedict as well as ALL buses to Robert F. Hall CSS are cancelled today due to weather and road conditions.

• Kawartha Pine Ridge Public & Peterborough Victoria Northumberland Clarington Catholic: Bus and transportation service is cancelled to ALL schools in the STSCO jurisdiction for the day.

• Near North Public & Nipissing-Parry Sound CathoIic: Bussing for all weather corridors are cancelled today.

• Rainbow Public & Sudbury Catholic: All school related transportation services operating in the districts of SUDBURY, ESPANOLA, MASSEY AND MANITOULIN are cancelled today.

• Simcoe County Public & Simcoe Catholic: Busses are cancelled for Muskoka.

• Thames Valley Public & London CathoIic: Busses are cancelled today for Middlesex, Oxford, and Elgin Counties and Red Zone.

• Trillium Lakelands: All school vehicles to schools in all Zones for Trillium Lakelands District School Board have been cancelled.

• Upper Grand Public & Wellington CathoIic: All busses in Divisions 2, 3, and 4 are cancelled today.

French Schools

• Conseil catholique MonAvenir: Busses are cancelled for schools in Peterborough.

• Conseil scolaire catholique Providence: Busses are cancelled for Oxford, Middlesex, and Bruce-Grey.

• Conseil scolaire public du Grand Nord de l’Ontario (CSPGNO): All school related transportation services operating in the districts of SUDBURY, ESPANOLA, MASSEY AND MANITOULIN are cancelled today.

• Le Conseil scolaire public du Nord-Est de l’Ontario (CSPNE) & Conseil scolaire catholique Franco-Nord: Bussing for all weather corridors are cancelled today.

‘Snow Day’ Forecast: Icy Conditions Could Give Some Students an Early Start to Holiday Break Across Southern Ontario on Friday

For an updated list of school bus cancellations & school closures, please visit our live article: https://instantweatherinc.com/article/2025/12/19/bus-cancellations

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A messy roller coaster of weather is expected across Southern Ontario throughout the day on Friday. It will begin with rain overnight, switching over to heavy snow right around the height of the morning commute. Temperatures will then plunge quickly, leading to the development of icy conditions.

To make things even more complicated, lake effect snow is expected to redevelop east of Lake Huron and Georgian Bay later in the day, with locally 10 to 20 cm of snow possible by Friday evening.

With the rain changing to snow, lining up with the morning commute and temperatures dropping through the freezing mark, there is potential for school bus cancellations, especially in rural areas.

The temperature drop is expected to be fairly gradual, which makes it uncertain whether Environment Canada will issue flash freeze warnings. That uncertainty also makes it harder to determine whether conditions will reach the threshold needed for widespread cancellations.

Our highest confidence lies in two regions that tend to be more sensitive to winter weather due to the large number of rural routes they serve. These include the North Hastings zone under Tri-Board Student Transportation Services and the Parry Sound and East Parry Sound regions within the Near North District School Board.

We have assigned these areas a 75 percent chance of bus cancellations. At this point, we are leaning toward cancellations, but not strongly enough to support a higher probability.

Across the broader rural portions of Central, Eastern and Southwestern Ontario, we have assigned a 50 percent chance of school bus cancellations, as conditions could easily go either way. We do expect several cancellations within this widespread zone.

This includes areas covered by the Avon Maitland District School Board, the Trillium Lakelands District School Board, North Bay under the Near North District School Board, Peterborough County within the Kawartha Pine Ridge District School Board, and much of Tri-Board Student Transportation Services. Kingston and Prince Edward County under Tri-Board sit lower at 25 percent. This zone also includes the Madawaska region within the Renfrew County District School Board.

Outside of these areas, there is still a slight chance of cancellations, although we are leaning toward buses running in most cases. As such, we have assigned a 25 percent chance to Lambton and Chatham-Kent within the Lambton Kent District School Board, Middlesex and Oxford counties under the Thames Valley District School Board, Dufferin and Wellington counties within the Upper Grand District School Board, the Simcoe West and Simcoe North weather zones, as well as the remaining portions of the Renfrew County District School Board and the Upper Canada District School Board.

For the rest of Southern Ontario, which is largely covered by more urban school boards, cancellations are unlikely. This includes Windsor under the Greater Essex County District School Board, London and Waterloo under the Thames Valley District School Board and Waterloo Region District School Board, the Greater Toronto Area including Toronto, Peel, York, Durham and Halton, the Simcoe Central and Simcoe South zones, and the Ottawa region.

Conditions in these areas are not expected to meet typical cancellation thresholds. Still, we have assigned a small 5 to 10 percent chance to account for the possibility of a few surprise decisions if icy conditions become more impactful than currently expected.

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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.

Southern Ontario: ‘Snow/Ice Day’ Forecast for Thursday, December 18, 2025

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No major winter weather is expected across Southern Ontario on Thursday, and because of this, widespread school bus cancellations are unlikely.

That said, many areas have seen temperatures climb above freezing during the day on Wednesday, followed by an expected drop back below freezing later tonight and into early Thursday morning. This setup could allow for some localized icy conditions to develop, especially on rural roads.

Because of this possibility, we have assigned a widespread low to very low chance for an “ice day” across parts of Central and Eastern Ontario, as well as higher elevation areas of Southwestern Ontario.

We are not expecting cancellations, but if back roads become icy enough in a few localized spots, a surprise decision cannot be completely ruled out.

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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.

Blizzard Conditions Expected as High Impact Winter Storm Targets the Prairies Wednesday With Up to 30cm of Snow

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The next Clipper to cross the Prairies, the latest in the seemingly never-ending train of such systems, is setting up to be the most impactful of the season so far. This system will bring 15+cm of snow to all three provincial capitals, along with blizzard conditions to parts of Southern Saskatchewan and Manitoba Wednesday and into Thursday. There has been little change in the projected track of the Clipper since we shared our preliminary forecast Monday evening so many of the details remain the same and total snowfall accumulations have become clearer.

Alberta

Snow has fallen throughout the day Tuesday in the Rockies and this will continue into the evening and overnight. Late Tuesday evening, the snow will begin to expand southeastward from Northwestern Alberta as the low pressure center associated with the system starts to make its way into the province. The leading edge of the snow will cross Alberta through the early morning hours, reaching the Saskatchewan border shortly before sunrise.

The rdps model showing precipitation type and intensity at 5Am MT on Wednesday, courtesy of WeatherBell.

The snow will be fairly light to moderate for most of the impacted areas of Alberta. A majority of Southern Alberta can expect less than 5cm since the precipitation will start off as a mixture of rain and freezing rain, possibly for several hours, due to the temperatures hovering around the freezing mark. However, there will be a switch over to snow as the temperatures drop, leading to the freezing of wet surfaces and minimal snow accumulation.

To the north, the lack of warm air and more consistent snowfall will result in greater accumulations. A large swath of Central Alberta and into Northern Alberta can expect 5-15cm of fresh snow, falling at rates of 1-2cm/hr during the late morning and early afternoon. In the Edmonton area and southeastward through Wainwright to the Saskatchewan border, heavier snow is expected to fall, possibly exceeding 3cm/hr, leading to rapid accumulation above 15cm.

In the early afternoon, the snow will begin to taper off from northwest to southeast across Alberta and it will gradually exit the province during the evening.

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The rdps model showing precipitation type and intensity at 12Pm CST on Wednesday, courtesy of WeatherBell.

Saskatchewan

As the system makes its way through Saskatchewan, the situation becomes quite a bit messier. The leading edge of the precipitation will start to push through the province during the morning mostly as snow, but with rain, freezing rain, and ice pellets in the mix through the warmer air that will be present in Southern Saskatchewan. The freezing rain could last for several hours, resulting in a few millimetres of ice buildup on untreated surfaces. However, as the low tracks eastward during the afternoon, cold air will wrap around and result in a freezing of wet surfaces and a period of snow that follows.

Meanwhile, across Central Saskatchewan, as the snow moves through the province, it will intensify. Heavy snowfall rates up to 4cm/h during the afternoon and evening will result in the widespread quick accumulation of 15-30cm over an area that includes both Saskatoon and Regina.

The rdps model showing precipitation type and intensity at 7Pm CT on Wednesday, courtesy of WeatherBell.

Manitoba

The snow will finally start to cross into Manitoba in the late morning. There will be a much smaller pocket of warm air that will be isolated to the southwest corner of the province, so while there will be a chance for a brief period of freezing rain in Manitoba, the risk won’t be as prolonged or as widespread as in Saskatchewan.

The area of heavier snowfall will spread from Central Saskatchewan into Central Manitoba through the afternoon and evening, where it will also result in a widespread 15-30cm of fresh snow, including in Winnipeg.

During the evening, the system will begin to shift and start to track more southward as it also loses some intensity. This will bring the main band of snow into Southeastern Saskatchewan and Southern Manitoba overnight and through Thursday morning.

In Saskatchewan, the snow will taper off starting shortly after midnight and exit the province by around sunrise. The snow will continue for a few extra hours in Manitoba, starting to dissipate during the early morning hours and eventually finishing in the southeast corner of the province in the afternoon.

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This only covers the snowfall aspect of this storm, but there is one major factor left to consider: the wind. Strong winds are expected to develop Wednesday morning and continue through the afternoon and evening before dying down overnight across the Prairies. We’re looking at widespread wind gusts over 60km/h and likely exceeding 100km/h, particularly in Southern Alberta and Saskatchewan. There is even the possibility of damaging wind gusts that approach 130km/h in parts of Southern Alberta!

While the most intense gusts will not coincide with the area where the heaviest snow is expected to fall, gusts above 60km/h will be more than enough for blizzard conditions to develop across Central Saskatchewan and into Central Manitoba starting in the afternoon and lasting into the overnight hours. This will likely result in large stretches of multiple highways being closed due to very poor visibility along with rapid accumulation of snow on the road surfaces.

For the rest of the region, where the wind gusts could be stronger, even a little bit of snowfall could severely impact visibility throughout the day.

Travelling in these conditions can extremely dangerous so please plan ahead, try to limit any travel, and stay safe!

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Southern Ontario: ‘Snow/Ice Day’ Forecast for Wednesday, December 17, 2025

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Patchy freezing drizzle or light freezing rain is expected to develop across portions of Southwestern, Central and Eastern Ontario overnight Tuesday and into Wednesday morning.

While this freezing rain risk is not expected to be particularly impactful or widespread, it could still lead to a thin glaze of ice forming on untreated surfaces. This includes rural roads, sidewalks and vehicles, especially in areas where temperatures hover near the freezing mark through the night.

At this time, conditions are not expected to reach the threshold that would normally prompt widespread school bus cancellations. However, we cannot completely rule it out, especially if Environment Canada issues advisories overnight or if the freezing rain ends up being more widespread than currently forecast.

The most likely region to see an “ice day” is the North Hastings zone within Tri-Board Student Transportation Services. This area has a long history of being particularly cautious, largely due to its extensive network of rural routes where back road conditions can deteriorate quickly, even during relatively minor icing events. We have assigned this region a 25 percent chance to reflect that slightly elevated risk, though the overall lean remains toward buses running without major issues.

Elsewhere across the rural portions of Eastern, Central and Southwestern Ontario, we have assigned a low 5 to 10 percent chance of cancellations. Most school boards are expected to operate normally on Wednesday, but a few localized decisions cannot be ruled out depending on overnight road conditions.

This includes areas covered by Tri-Board, the Renfrew County District School Board, the Upper Canada District School Board, the Kawartha Pine Ridge District School Board, the Trillium Lakelands District School Board, the Near North District School Board, the Simcoe County District School Board, the northern portion of the Durham District School Board, the Upper Grand District School Board, the Bluewater District School Board and the Avon Maitland District School Board.

Outside of these regions, no weather-related school bus cancellations are expected on Wednesday. So for now, it looks like homework remains on the schedule.

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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.

ONTARIO: Environment Canada Forecasting Snow, Flash Freezing, Heavy Rain, Strong Winds and Extreme Cold This Week

A very active stretch of weather is expected across Ontario this week, with strong winds, snow, blowing snow, ice, heavy rain, and extreme cold all making appearances. Below is a day-by-day breakdown summary based on the latest Environment Canada forecast.

Tuesday, December 16:

- Strong southwest winds gusting up to 70 km/h for areas northeast of Lake Superior, Lake Huron and Georgian Bay, including parts of Manitoulin Island.

- Risk of flash freeze in northwestern Ontario as temperatures drop quickly, creating hidden ice on roads and walkways.

- Winds ease by late Tuesday night into early Wednesday.

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Wednesday, December 17:

- Significant wind chills near -40°C in far northwestern Ontario.

- Strong winds along the northeastern shores of Lake Erie and Lake Ontario, with gusts up to 80 km/h.

- Brief burst of snow and blowing snow across northeastern Ontario as a cold front sweeps through.

- Snow spreads into northwestern Ontario later in the day and continues overnight.

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Thursday, December 18:

- Strengthening low-pressure system brings 20–30 cm of heavy snow north of Lake Superior toward the Quebec border.

- Additional 5–15 cm of snow across northern Ontario.

- 15–25 mm of rain in southern Ontario on frozen ground, increasing localized flooding risk.

- Rain transitions to snow Thursday evening as temperatures fall.

- Extreme wind chills near -45°C in far northwestern Ontario.

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Friday, December 19:

- A flash freeze risk across southern Ontario during the morning commute as temperatures plunge.

- Snow squalls east of Lake Huron and Georgian Bay may deliver 5‑15 cm of snow and create near-zero visibility at times.

- Additional 5‑10 cm of snow possible across northeastern Ontario.

- Extreme wind chills of -40 to -45°C persist across northwestern and far northern Ontario.

- Continued risk of frostbite and hypothermia due to the bitter cold in the northwest.

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Long story slightly longer, a prolonged stretch of active weather is expected with high winds, snow, flash freezing, rain and extreme cold affecting different parts of Ontario. Stay safe and warm, everyone and make sure to download our free app InstantWeather to get the most up-to-date, detailed forecast for your specific location.

First Look at the Major Snowstorm Set to Impact the Prairies This Week

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After a seemingly constant stretch of back-to-back clippers bringing brief blasts of snow, we’re finally looking at a proper snowstorm across the Prairies this week. While this will be another clipper, it will be much more impactful, bringing periods of heavy snow to Edmonton, Saskatoon, Regina, and Winnipeg. Here’s a preliminary look at roughly what can be expected, but keep in mind that exact timing and snowfall amounts will likely change between now and the start of the event.

The snow is set to begin late Tuesday or very early Wednesday morning in the Rockies and Northern Alberta before gradually spreading eastward with the trajectory of the associated low. The leading edge of the snow will cross into Saskatchewan before sunrise Wednesday and then into Manitoba by the late morning or early afternoon.

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The snowfall should be fairly moderate as it tracks across Alberta before it starts to taper off in the evening. To the east, on the other hand, the snow is expected to intensify Wednesday afternoon in Saskatchewan and in the evening in Manitoba, leading to a significant swath of up to 30cm of heavy snowfall by the noon hour on Thursday.

To complicate matters further, strong winds with gusts exceeding 100km/h are expected across the Southern Prairies beginning Wednesday afternoon and continuing overnight. This will very likely lead to white-out conditions, possibly even reaching the threshold to be considered a blizzard, in Southern Saskatchewan and Manitoba that will probably result in highway closures.

It’s also worth noting that in the warm sector, along the southern edge of the snow, there will be the possibility of a mixture of rain, freezing rain, and ice pellets which would be followed by snow as the temperatures fall. We will have more information on this risk, along with further details regarding the entire storm in our full forecast that will be posted Tuesday evening.

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Southern Ontario: ‘Snow Day’ Forecast for Tuesday, December 16, 2025

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We are expecting a fairly quiet day weather-wise on Tuesday across Southern Ontario, with no major weather in place to cause widespread travel issues.

Because of this, there is nothing in the forecast that would suggest a strong likelihood of school bus cancellations.

The only area with any notable chance is the Parry Sound region under the Near North District School Board, where a snow squall warning remains in effect. That activity is expected to weaken overnight, making it questionable whether it will have any meaningful impact on the morning commute.

Even so, given this school board’s history of being particularly sensitive to weather conditions, we cannot completely rule out a surprise decision. As a result, we have assigned Parry Sound a 10 percent chance.

Outside of the Parry Sound area, no weather-related school bus cancellations are expected on Tuesday.

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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.

Southern Ontario: ‘Snow Day’ Forecast for Monday, December 15, 2025

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After an active weekend that featured periods of snow squall activity across portions of Southern Ontario’s snowbelt, conditions are expected to steadily improve later Sunday evening as the lake effect weakens and winds begin to ease.

Because of this, there are no major weather concerns expected overnight that would normally keep school buses off the roads on Monday. Most regions should see calmer conditions by the time the morning bus run begins.

That said, we cannot completely rule out a few isolated cancellations tied to lingering blowing snow and rural roads that may remain snow covered following Sunday’s squalls. Any issues would be highly localized and mainly confined to areas that saw the most persistent snowfall.

If cancellations do occur, they would most likely be found in Huron County under the Avon Maitland District School Board, Middlesex County within the Thames Valley District School Board, and Lambton County for the Lambton Kent District School Board.

We have assigned these regions a 25 percent chance of a snow day on Monday to account for the potential for rural route issues. Widespread cancellations are not expected.

Elsewhere across the snowbelt, we have maintained a low to very low chance simply to account for the outside possibility of a surprise decision.

If a surprise cancellation does occur outside of the regions mentioned above, the most likely candidate would be the Near North District School Board. Some light snow and lake effect activity may redevelop there later in the day, and this board has a history of being proactive when Environment Canada issues alerts. If any alerts are in place by early Monday morning, some cancellations are possible.

For the rest of Southern Ontario, no school bus cancellations are expected on Monday. So for now, it looks like homework is back on the menu.

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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.

Southern Ontario’s Never-Ending Winter Continues This Weekend as Squalls Threaten to Bring Up to 50cm of More Snow

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With a steady parade of system after system, along with lake effect snow in between, it’s certainly understandable that some parts of Southern Ontario are getting pretty fed up with all the snow. The snow continues to pile up, especially across the snowbelt regions!

It was only a few days ago that the Barrie area was slammed with intense lake effect snow, with up to 70cm reported in the hardest hit community of Angus. And that doesn’t even include what was already on the ground before this round of squalls moved through.

Regions east of Lake Huron, including Grey, Bruce, Huron and Perth counties, have also seen their fair share of snow so far this winter, with frequent lake effect events adding to an already deep snowpack.

Fortunately for snow lovers, and perhaps unfortunately for everyone else, the squalls are far from finished. The lakes remain wide open, and we are just getting into the heart of colder Arctic air. That combination will continue to provide plenty of fuel for additional rounds of lake effect snow in the coming weeks.

The next round of squalls is just around the corner, with activity expected to ramp up again as early as Saturday morning. The good news for areas that were recently hammered by the Georgian Bay squall, including Barrie and Wasaga Beach, is that you should catch a bit of a break this weekend. The bulk of the activity will focus farther north and west.

Those east of Lake Huron, including Huron, Bruce and Grey counties, are not as lucky. Lake effect snow off Lake Huron is expected to target these areas once again with repeated rounds of snow through the weekend.

This is shaping up to be a multi-day lake effect event, with squalls persisting through the weekend and possibly into Monday. Winds are expected to be somewhat unstable, which means the squalls will tend to drift around rather than remain locked over one specific area. Because of this, it’s unlikely we’ll see extreme localized totals like the 50 to 75cm that fell southwest of Barrie earlier this week.

That said, snowfall totals will still add up. The hardest hit areas, including Parry Sound, Bracebridge, Tobermory, Owen Sound, Hanover, Collingwood, Goderich and Grand Bend, can generally expect 25 to 40cm. Some pockets, particularly across Muskoka, could push closer to the 50cm mark.

PRECIP TYPE - MAP FROM WEATHERBELL

The event is expected to get underway early Saturday morning as a brief southwesterly wind develops. A weak system moving through the region will become enhanced by the lakes, producing short bursts of heavy snow.

This could impact areas northeast of Georgian Bay as well as regions northeast of Lake Erie and Lake Ontario. Places like Parry Sound, North Bay, Niagara and Kingston could see a quick 5 to 10cm early Saturday morning, along with near-zero visibility at times.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

As that system exits, winds will become more westerly, shifting the focus back to Georgian Bay and Lake Huron through Saturday afternoon and evening.

Current model guidance shows a fairly potent and narrow band setting up near the northern tip of the Bruce Peninsula, stretching across Georgian Bay and coming inland near Port Carling and Bracebridge. Keep in mind that even small shifts in wind direction could push the heaviest snow several dozen kilometres north or south.

Very poor to hazardous driving conditions are expected along the Highway 400 and Highway 11 corridors in this area. Highway closures are not out of the question, especially given how quickly conditions can deteriorate.

Additionally, somewhat weaker bands are also expected to develop off Lake Huron, impacting the Owen Sound to Goderich corridor. There remains uncertainty regarding exactly where these bands will set up and whether they consolidate into a more dominant squall.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

Later Saturday, a subtle wind shift will cause the main Georgian Bay squall affecting Muskoka to briefly drift south into Simcoe County. This could bring a short period of heavy snow overnight Saturday to Midland, Orillia and Barrie. Accumulation here should be limited, generally around 5 to 10cm, as the squall will be moving through fairly quickly.

A similar evolution will occur east of Lake Huron, with the squall drifting from Tobermory down through the Bruce Peninsula and into southern Bruce and Grey counties overnight. This activity will continue as the squall settles farther south and west of London under a more north-northwest flow.

PRECIP TYPE - MAP FROM WEATHERBELL

By Sunday morning, the strongest lake effect activity is expected to be found off Lake Huron, affecting the Grand Bend to London corridor. At this point, it appears the core of the squall should remain just west of London, impacting areas like Strathroy, though brief pushes into the city are still possible.

The Georgian Bay squall will temporarily weaken as winds become less favourable for a strong lake fetch. This should restrict activity mainly to shoreline areas near Meaford and Collingwood for a time.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

That break will be short-lived. By Sunday evening, increasing winds will allow lake effect snow off Georgian Bay to intensify once again. Some models show moderate to heavy snow developing from Meaford through Collingwood and extending toward the Orangeville region overnight, before the lake effect machine is shut down by an approaching system on Monday morning.

Lake Huron squalls will continue through this time, remaining heavy at times across Huron County, Grand Bend and areas west of London. As with earlier periods, most of the heaviest snow should stay just to the west of the city.

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Because the squalls will be shifting around, snowfall will be more evenly distributed across a wider area. We aren’t expecting extremely high localized totals, but many communities will still share in the heavy snowfall. By the end of the weekend, most areas east of Lake Huron and Georgian Bay could see totals ranging from 25 to 50cm.

The usual lake effect disclaimer applies. Some locations will inevitably end up just outside the heaviest bands, but the contrast should be less dramatic this time since most snowbelt areas will be impacted at some point.

The main target zones include areas east of Georgian Bay, such as Parry Sound, Rosseau, Port Carling, Bracebridge and Port Sydney, along with much of Bruce, Grey, Huron and Middlesex counties east and southeast of Lake Huron. This includes communities like Tobermory, Wiarton, Lion’s Head, Owen Sound, Meaford, Collingwood, Flesherton, Hanover, Chatsworth, Port Elgin, Kincardine, Mildmay, Point Clark, Wingham, Goderich, Clinton, Exeter, Lucan, Grand Bend and Strathroy.

Snowfall totals will drop off quickly outside of these regions, as lake effect snow remains highly localized. However, as mentioned earlier, a brief 5 to 10cm is still possible Saturday morning for parts of Niagara and the Kingston area due to lake-enhanced snow from the passing system.

For the rest of Southern Ontario, expect around 2 to 5cm from that system on Saturday, with most locations likely closer to the lower end of that range outside of the snowbelt.

Southern Ontario: ‘Snow Day’ Forecast for Friday, December 12, 2025

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Snow squalls that remained locked in place east of Lake Huron and southeast of Georgian Bay brought a second straight snow day to many students across the snowbelt, with school buses cancelled both Wednesday and Thursday. But for anyone hoping to turn this into a rare three-day streak and stretch the weekend a little further, the chances are not looking nearly as promising.

Through Thursday evening, the squalls have already begun to weaken, with intensity dropping off compared to earlier in the day. That downward trend is expected to continue overnight as winds ease and the lake effect snow machine gradually winds down. By morning, conditions should look much calmer, at least in terms of new snowfall.

However, despite the improvement in weather, many communities have spent the past 12 to 24 hours getting buried in persistent snow squalls. Road crews will be working hard overnight, but in the hardest-hit areas, it is unlikely that every rural route will be fully cleared by the time the morning bus run begins. Even without active squalls on Friday morning, the snow already on the ground may be enough for some school boards to consider keeping buses off the road for a third day.

Confidence in widespread cancellations is not particularly high, so we have capped the maximum at a 50 percent chance. This zone includes Huron County under the Avon Maitland District School Board, southern Bruce County within the Bluewater District School Board, and the Simcoe West zone under the Simcoe County District School Board. These regions experienced the most persistent squall activity today, and their large number of rural routes increases the likelihood that cleanup may not be fully completed by morning.

Outside this core area, a slight chance (25 percent) has been assigned to several surrounding regions. This includes Middlesex and Oxford counties within the Thames Valley District School Board, Perth County for AMDSB, the remainder of Bluewater, including northern Bruce County and all of Grey County, as well as Simcoe Central and Simcoe South. While buses should be able to run in most of these locations, the final decision will depend heavily on how effective overnight cleanup efforts are. Simcoe’s Central and South zones are also more urban, and historically, these areas require more severe conditions before cancellations are considered.

For the remainder of Southern Ontario, a snow day on Friday appears unlikely. Most regions fall into the very low to low category, with no significant weather expected overnight or Friday morning that would normally prompt cancellations. Unless there are unexpected localized issues left behind from today’s squalls, most students should plan for a regular school day.

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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.

Southern Ontario: School Bus Cancellations and Closures for Thursday, December 11, 2025

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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

• 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.

• Kawartha Pine Ridge Public & Peterborough Victoria Northumberland Clarington Catholic: all busing and school transportation is cancelled today for all of the STSCO jurisdiction

• Renfrew County Public & Renfrew County Catholic: Zone 4 Madawaska area transportation services ONLY are cancelled due to observed poor road conditions.

• Simcoe County Public & Simcoe Catholic: Busses are cancelled for the West, Central, and South Zones.

• Thames Valley Public & London CathoIic: Busses are cancelled and schools are CLOSED for Middlesex, Oxford, and Elgin Counties, and Red Zone.

• Tri-Board: transportation is cancelled in North Hastings, Centre Hastings, North Lennox & Addington, Central Lennox & Addington, North & Central Frontenac and South Frontenac weather zones today.

• Upper Canada Public & Eastern Ontario CathoIic: All transportation is cancelled due to forecasted severe weather and road conditions.

French Schools

• Conseil des écoles publiques de l’Est de l’Ontario (CEPEO): Busses are cancelled for Brockville, Carleton Place, Arnprior, Prescott-Russell, Marionville, and Merrickville & Kemptville

• Conseil catholique MonAvenir: Busses are cancelled for schools in Simcoe and Peterborough

• Conseil scolaire de district catholique de l'Est Ontarien (CSDCEO): All busses are cancelled

• Conseil des écoles catholiques de langue française du Centre-Est: Busses are cancelled for Brockville, Carleton Place, Arnprior, Prescott-Russell, Marionville, and Merrickville & Kemptville

• Conseil scolaire catholique Providence: Busses are cancelled for Simcoe West, Central, and South Zones, Oxford, Middlesex rural routes, and Bruce-Grey

• Conseil scolaire Viamonde: Busses are cancelled for Simcoe West, Central, and South Zones, Oxford, Middlesex rural routes, and Bruce-Grey

Barrie Area to Be Buried in Up to 40 to 75 cm of Snow on Thursday as Arctic Air Fuels Dangerous Snow Squalls

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Snowfall from the Alberta Clipper that slid through Southern Ontario earlier on Wednesday is beginning to taper off. The system has left its mark across the region with a widespread 10 to 20cm of snow in some areas, while others saw a slushy mix.

While the clipper may be done, the snowfall story is not. As the system pulls away, it ushers in a polar blast of cold air overnight on Wednesday. This air, combined with strong northwesterly winds, will kick the lake effect snow machine back into gear off Lake Huron and Georgian Bay.

Intense snow squalls across Simcoe, Huron and Perth counties throughout Thursday are likely to create dangerous conditions. Frigid wind chills paired with near-zero visibility will make travel extremely difficult and even life-threatening if you become stranded.

The Georgian Bay squall is expected to be particularly intense. A narrow corridor from Wasaga Beach through southwest Barrie, including Angus, Innisfil and into Bradford, may see the band lock in place for more than six hours. Snowfall rates could exceed 5cm per hour.

Localized totals around the Barrie area could approach 50 to 75cm in the hardest hit pocket. Some high resolution models even suggest 100cm is not completely off the table.

East of Lake Huron, activity will be persistent from Thursday morning through the evening. The lake effect here appears more spread out rather than focused on one specific pocket. The heaviest totals are expected across Huron and Perth counties, where up to 50cm is locally possible.

PRECIP TYPE - MAP FROM WEATHERBELL

As of Wednesday evening, we are already seeing some activity begin ramping up off the southeast shoreline of Lake Huron and Georgian Bay. This will continue to organize after midnight into the early hours of Thursday.

By early morning, we expect the most focused squalls to target the Goderich to London corridor off Lake Huron and the Collingwood to Bradford stretch off Georgian Bay.

Keep in mind, this is a rough idea from the models, and the exact placement can shift if the wind direction changes even slightly.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

By the time the morning commute begins around 6 AM, snow squall activity will intensify as the Georgian Bay band becomes extremely narrow and focused. Some model runs have it stretching from Wasaga Beach through Angus and into the Innisfil to the Newmarket area.

There remains uncertainty in how much snow the City of Barrie itself will receive. The gradient between limited snow and a huge dumping will be very tight. The south and west ends are most likely to see major impacts, although it would not take much of a shift for the band to slide directly into the city.

The Lake Huron activity will begin to spread out with moderate snowfall covering much of Huron and Perth counties, including Goderich, Wingham, Stratford and Listowel. Because the band is more diffuse, there will not be one intense pocket as we expect with the Georgian Bay squall.

ESTIMATED WIND CHILL - MAP FROM WEATHERBELL

A major factor with this round of squalls that makes the situation more dangerous is the very cold wind chills. When you wake up Thursday, wind chills will make it feel like the -20s. Combined with squalls at the same time, the risk to anyone stranded on the roads increases significantly.

Aside from the cold creating hazards, it will also boost snowfall rates. Colder air produces drier, fluffier snow, which allows the same amount of moisture to create a larger volume of accumulation.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

Little will change heading into the late morning as the Georgian Bay squall remains locked in place near the Barrie area. The band could edge far enough north to put the city core into the bullseye. Keswick may also be brought into the heavy snow as the band wobbles.

For the Lake Huron squall, the band may briefly become more focused as a single strong line cutting through Goderich and into Stratford and Woodstock. Depending on slight track shifts, Kitchener or Hamilton could also be affected at times.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

Conditions are expected to deteriorate further into the afternoon. The Georgian Bay squall appears to strengthen with hourly snowfall rates easily exceeding 5cm and possibly pushing 10cm. At this point, the most intense pocket is shown just southwest of Barrie, with Angus being hit hardest.

The Lake Huron squall will also become more organized with an impressive fetch stretching all the way toward Lake Erie and impacting Woodstock and Norfolk.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

There is significant concern for the Hwy 400 corridor during the afternoon and evening commute from just south of Barrie to roughly Aurora. This section of highway will likely become snow covered with road crews struggling to keep up with extreme snowfall rates. Combined with whiteout conditions, travel in this zone should be avoided unless absolutely necessary.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

As we head into the evening and just past midnight, the squalls will retreat closer to the lakeshores as winds weaken and moisture supply cuts off. This will lead to activity tapering to lake effect flurries overnight into Friday morning.

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As always with snow squalls, snowfall forecasts should be taken with a large grain of salt. While models are in good agreement on placement and intensity, nothing is guaranteed as conditions need to align perfectly.

With that being said, we believe the hardest hit zone will be along the southeastern Georgian Bay shoreline from Wasaga Beach through Angus and into northern York Region. Barrie sits right on the edge but could easily end up inside the bullseye. Snowfall totals here are likely to exceed 40cm and may approach 75cm. Around Angus is where models show the strongest signal.

A tight gradient will set up with the north and east sides of Barrie, along with Keswick, Bradford and Collingwood, likely seeing 25 to 40cm of snow.

East of Lake Huron including Kincardine, Minto, Point Clark, Wingham, Listowel, Mitchell, Stratford, Exeter and Goderich, totals of 25 to 40cm are expected. Localized amounts up to 55cm are possible if a squall locks in place for several hours.

Totals of 15 to 25cm are possible for Midland and into central York Region including Newmarket and Aurora as well as Durham Region around Uxbridge. These areas will see occasional bursts of heavy snow near the edge of the main bands.

Southern Bruce and Grey counties along with Wellington County including Arthur and Oxford County may also see 15 to 25cm but totals depend on how far inland the bands extend.

Between 5 and 15cm is possible across the rest of York and Durham Region as well as northern Simcoe County including Orillia, Owen Sound, Shelburne, Fergus, Kitchener, Brantford and London. These locations sit farther from the core activity so most will see closer to 5cm with higher amounts only if a band stretches farther inland.

Less than 5cm is expected outside the snowbelt regions including Eastern Ontario, Deep Southwestern Ontario and the Golden Horseshoe.

‘Snow Day’ Forecast: Snow Squalls May Deliver a Second Snow Day to Some Students in Southern Ontario on Thursday

For an updated list of school bus cancellations & school closures, please visit our live article: https://instantweatherinc.com/article/2025/12/11/bus-cancellations

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As snowfall from the Alberta clipper tapers off across Southern Ontario, attention quickly shifts to the next round of winter weather. Snow squalls are expected to develop off Lake Huron and Georgian Bay as early as Wednesday evening, continuing through the night and into Thursday morning.

These squalls have the potential to create dangerous travel conditions in portions of the traditional snowbelt, including Huron County, Grey-Bruce and Simcoe County. Intense snowfall rates combined with near-zero visibility may make it difficult for rural routes to be cleared in time for the morning commute. Because of this, some regions could be facing the possibility of a second straight snow day on Thursday.

The highest chance for another round of bus cancellations includes Huron County within the Avon Maitland District School Board, the Kincardine area within the Bluewater District School Board and the Simcoe West weather zone under the Simcoe County District School Board.

We have assigned these regions a 75 percent chance. While confidence is fairly strong that conditions will be poor enough to warrant cancellations, these boards have been more hesitant this season, even with strongly worded alerts from Environment Canada. That hesitation keeps this group just below the highest tier.

Surrounding regions sit in our 50 percent category, where conditions could genuinely go either way. This includes Middlesex and Oxford counties within the Thames Valley District School Board, Perth County under AMDSB and the Hanover, Southampton and Meaford areas within Bluewater. It also includes the Simcoe Central and Simcoe South weather zones. For these regions, much will depend on where the most persistent squalls set up Thursday morning. Given how lake effect snow can shift quickly, confidence stays right in the middle.

We have also assigned a 50 percent chance to parts of Eastern Ontario, including North Hastings, North Lennox and Addington and North and Central Frontenac within Tri-Board Student Transportation Services. The Madawaska zone within the Renfrew County District School Board also sits at 50 percent. Snow from the Alberta clipper may linger long enough to leave rural roads snow-covered into the morning, and these school boards tend to be more sensitive to deteriorating conditions.

A broader 25 percent zone covers the remaining rural portions of Eastern and Central Ontario. This includes the Upper Canada District School Board, the rest of the Renfrew County District School Board, the southern portions of Tri-Board, Peterborough County within the Kawartha Pine Ridge District School Board and regions covered by the Trillium Lakelands District School Board.

Snow should be wrapping up well before the bus run, but with temperatures dropping overnight and the potential for icy patches, we cannot completely rule out a few isolated cancellations. It remains questionable, but still possible.

We have also assigned a 25 percent chance to some snowbelt-adjacent communities that may be brushed by squalls at times but are expected to remain outside the core impact zone.

This includes Owen Sound and the Bruce Peninsula within the Bluewater District School Board, Dufferin County under the Upper Grand District School Board, the York Region District School Board and the Simcoe North weather zone. Occasional bursts of heavier snow are possible, but sustained conditions leading to cancellations are less likely.

Elsewhere across Southern Ontario, most school boards fall into the very low to low category. A few urban boards may keep a slight chance simply to account for any delays in overnight cleanup from Wednesday’s storm, but given that these same boards did not cancel on Wednesday, it is very unlikely they will decide to cancel on Thursday.

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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.