Environment Canada warns of high heat and humidity for southern Quebec and Ontario

The heat is expected to move into Montreal on Wednesday and is forecast to last until Saturday, with little relief at night. Parts of Quebec’s Outaouais, Lanaudière, Laval, Laurentians, Montérégie, Centre-du-Québec and Estrie regions will also be affected.

As is tradition, Canada Day is also considered Quebec’s unofficial moving day, when leases expire for many households and streets are lined with trucks and littered with discarded items. This year, renters will be loading and unloading moving trucks in temperatures forecast to be in the 30 to 33 C range with humidex readings up to 44.

Montreal Mayor Soraya Martinez Ferrada said the city is making sure its water parks and cooling centres are up and running, especially in places where homeless and vulnerable people gather.

“I see what’s happening in Europe,” she said about the killer heat wave moving across the continent. “We’ve gone through this in our city. We just want to make sure that people know where to go.”

France recorded around 1,000 excess deaths last week at the height of its record-smashing heat wave, the country’s public health agency said Sunday, as several other European countries recorded their highest-ever temperatures.

Extreme heat is also one of Canada’s most dangerous climate risks. During six heat waves last summer, Toronto emergency rooms fielded 74 heat-related visits, the local health unit said.

Montreal’s public health department says it received three reports of possible heat-related deaths during an August 2025 heat wave. That same heat wave over southern Quebec was found to be at least two to 10 times more likely due to climate change, an analysis by federal scientists suggested.

Toronto and Hamilton are both exploring bylaws that would require landlords to cool units below 26 degrees.

Meanwhile, new Ontario rules taking effect Wednesday will prohibit landlords from preventing tenants from installing an air conditioner, provided the tenant gives written notice and meets certain other conditions.

Environment Canada says extreme heat puts people at risk of exhaustion or heatstroke and poses a particular danger for vulnerable people. The agency is asking people to check on older or at-risk people and to watch for early signs of heat exhaustion, which include headache, nausea, dizziness, thirst and intense fatigue.

This report by The Canadian Press was first published June 29, 2026.

— With files from Jordan Omstead in Toronto and The Associated Press

Morgan Lowrie, The Canadian Press

by The Canadian Press

Environment Canada warns of high heat and humidity for southern Quebec and Ontario

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