***NOTE: YOU CAN CLICK ON THE MAP TO OPEN A ZOOMABLE IMAGE***

While much of late May across Southern Ontario was dominated by unseasonably cool weather, the start of June is shaping up to be a very different story. Over the past few days, temperatures have rebounded to near-seasonal levels across the region, and that’s just a preview of what’s ahead. But enjoy it while you can because a noticeable cool down is expected later this week.

This early June heat has also arrived with a layer of upper-level smoke drifting in from wildfires burning across Western Canada. This smoke has caused a light haze in the sky, giving the air a faint smoky smell, dimming the sun, and slightly suppressing daytime temperatures compared to what we would have seen under clear skies.

The good news is that much of this smoke is expected to clear out across Southern Ontario overnight into early Wednesday morning. While some lingering smoke may remain high up in the atmosphere, it shouldn’t be as thick or widespread as what we’ve seen over the past 36 hours.

With clearer skies, daytime heating will be more effective, giving temperatures a better shot at reaching their full potential. On Wednesday, we’re expecting highs to climb into the upper 20s and possibly even low 30s in some spots.

A cold front sweeping across the province late Wednesday will bring a shift in the pattern, knocking temperatures back below seasonal for the latter half of the week. This front is also expected to trigger a line of thunderstorms, some of which may be marginally severe.

Primary threats include damaging wind gusts up to 90 km/h, pockets of quarter-sized hail, and localized flooding from slow-moving storms. There is also a very low risk of an isolated tornado, but given the weak storm environment, this threat is quite uncertain and likely limited.

**ESTIMATED AIR TEMPERATURE** - MAP FROM WEATHERBELL

Much of Wednesday will start off hot and hazy, especially across Southern Ontario. Temperatures will rapidly climb into the upper 20s by early afternoon ahead of the approaching cold front. In some areas, particularly Deep Southwestern Ontario, the Golden Horseshoe, and the Ottawa Valley, temperatures could push into the low 30s.

That said, locations along the immediate shorelines of the Great Lakes will likely remain a few degrees cooler due to the lake breeze. These areas, including communities along Lake Erie, Lake Ontario, Lake Huron, and Georgian Bay, should see highs closer to the low to mid-20s.

As the cold front begins moving in from the northwest, starting around 2 to 4 PM near the Bruce Peninsula and the North Bay and Parry Sound region, we’ll see an almost instant temperature drop. It could fall by as much as 10 to 15 degrees within a couple of hours. The front will then gradually push southeast through the rest of the afternoon and into the early evening hours.

As the temperatures rise, it’s crucial to keep our beloved pets safe and comfortable. Here are some essential tips to ensure your furry friends stay cool this summer:

🚗 Never Leave in Cars: Even with windows cracked, the temperature inside a car can rise dramatically in just a few minutes. On a 24°C day, the temperature inside a parked car can soar to 38°C in just 10 minutes. In 30 minutes, it can reach 49°C! Leaving your pet in a car can be deadly, so never leave them unattended.

If you see a pet left unattended in a car in Ontario:

Look for the Owner: Note the car's make, model, and license plate number. Go to nearby businesses to see if you can find the owner.
Call for Help: If you cannot find the owner, call your local animal control or police. You can call the OSPCA at 1-833-9-ANIMAL (264625). If you believe the animal is in immediate distress, call 911 immediately.
Stay with the Pet: Remain with the pet until help arrives.

🏡 Shade & Shelter: Make sure your pets have access to shaded areas to avoid direct sunlight. A cool, sheltered spot can make a big difference.

💧 Hydration is Key: Always provide fresh water for your pets. Dehydration can set in quickly, so keep their water bowl filled and in a shaded area.

🐕 Limit Exercise: Avoid walking your pets during the hottest parts of the day. Early morning or late evening walks are best to prevent overheating.

🐾 Paw Protection: Hot pavement can burn your pet's paws. Walk them on grass whenever possible, or use protective booties to shield their feet.

⚠️ Watch for Signs of Overheating: Symptoms include excessive panting, drooling, and lethargy. If you notice these signs, move your pet to a cooler area immediately and provide water.

**UPPER LEVEL SMOKE CONCENTRATION** - MAP FROM WEATHERBELL

Although the smoke won’t be nearly as thick as what we experienced Monday and Tuesday, some light to moderate upper-level smoke may still linger on Wednesday. Forecast models suggest the highest concentrations will likely be around the Golden Horseshoe, including the Greater Toronto Area, Hamilton, and the Niagara region.

There may still be a faint smoky smell in the air at times, but surface-level smoke isn’t expected to be heavy enough to significantly impact air quality. What it could do, however, is hold temperatures back by a couple of degrees in some spots since the sunlight won’t be able to fully break through the smoke layer.

By Thursday, most of this smoke should clear out completely. That said, some models are hinting at another round of wildfire smoke pushing into the region by late this week or into the weekend.

**SIMULATED RADAR** - MAP FROM WEATHERBELL

Along with cooler temperatures, the advancing cold front will bring the potential for thunderstorms across Southern Ontario. Current data suggests that a line of storms will begin forming early Wednesday afternoon, stretching from North Bay down into parts of Michigan.

As this front continues to track southeastward, conditions will become more favourable for some of these storms to become locally severe. Isolated threats include damaging winds, large hail, and heavy downpours. The highest risk zone appears to be in a corridor running from Deep Southwestern Ontario through Kitchener and Waterloo, into the Lake Simcoe region, and extending northeast into the Algonquin Park area.

The timing for the strongest activity looks to fall between 3 PM and 6 PM, though it could stretch a bit later, especially in areas near the border. Some model runs even show a rogue thunderstorm crossing into the Windsor or Sarnia area from Michigan during the evening hours.

The overall tornado threat remains low due to the weak storm environment and expected messy storm mode, but it is never zero. Sometimes we do see surprise spin-up tornadoes in Ontario, especially where lake breezes collide and enhance low-level rotation.

After sunset, the severe risk should wind down fairly quickly. However, a few non-severe thunderstorms may continue into the late evening and overnight as the front moves across the Golden Horseshoe and into Eastern Ontario.