Environment Canada issues yellow-level heat warning for southern Ontario and beyond to start work week

“A heat event begins Monday,” states the Environment Canada yellow-level warning.

The heat is back on. Environment Canada has issued a widespread yellow-level heat warning for southern Ontario and beyond to start the work week. “A heat event begins Monday,” stated the warning issued Sunday, July 12, just after 4 p.m., adding that it “will end either Wednesday evening or Thursday evening.”

Tuesday will mark the peak of this event with maximum temperatures expected to reach near 36 C in some areas along with humidex values of 38 to 45. Hot and humid air, the warning noted, can also bring deteriorating air quality, potentially pushing the Air Quality Health Index toward the high-risk category. The warning covers a vast area from Windsor to North Bay, Sault Ste.

Marie to Cornwall, and all points in between including Toronto. (To find your own local Environment Canada forecast just click on any of the links and put your own community in the prompt.) Pearson Airport in Mississauga, for instance, reached its forecast high of 28°C by mid-afternoon Sunday.

While overnight temperatures are forecast to fall to the mid-teens, the heat will ramp up quickly with forecasted highs of 32°C Monday, 36°C Tuesday, 33°C Wednesday, and 31°C on Thursday.