Southern Ontario’s epic heat streak faces a hiccup Monday
A more comfortable pattern is on the horizon for much of Eastern Canada to round out August
This year’s hot and steamy summer across southern Ontario hasn’t loosened its grip much. The season has been unshakably warm with limited cold fronts sweeping into the region.
The impressive heat streak is finally going to face a hiccup with a change arriving in time to begin the new workweek.
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Impressive stretch of summery warmth
As of August 17, the cities of Toronto, Hamilton, London, and Kingston were all riding marathon stretches of days with highs above 22°C.
Toronto has seen 64 consecutive days at or above 22°C, beginning June 15 and rolling straight through August 17. The streak stands at 66 days in Windsor, 63 days in Hamilton, 59 days in London, and 49 straight days of warmth over in Kingston.
Unusually warm nighttime lows are even more impressive. Toronto hasn’t dipped below 13°C since June 10, a run that threatens a 73-day streak set back in 2018.
These warm nights amplify the effects of heat, as cities retain warmth and air conditioning systems can’t catch a break.
Cooler air on the horizon, but is it cool enough?
A cold front pushing into southern Ontario will send temperatures dipping below seasonal across the region on Monday. Will the streak survive? It’ll be a close call.
It’s possible that highs on Monday peak just above the 22-degree mark, which means this marathon will continue for at least another couple of weeks. The coolest day we’ve seen in Toronto during this marathon stretch of warmth was a high of 22.8°C on July 18.
The forecast calls for an even 22°C in both Toronto and Hamilton, with temperatures coming in a few degrees warmer across the region from Windsor to Ottawa.
A fever in the lakes
All this warmth hasn’t just had an effect on humans and infrastructure.
The Great Lakes are currently running several degrees above seasonal compared to the 1995-2024 average.
All five bodies of water are running at least 2 degrees above seasonal for the middle of August. Surface temperatures on Lake Erie are hovering around 26°C, while readings on Lake Ontario came in around 25°C on August 17—the latter of which is an impressive 3°C above average.
These unusually toasty lake temperatures have helped keep conditions from cooling off through the overnight hours in recent weeks.