‘Heat dome’: Ontario, Quebec battle scorching temperatures

CP24’s Bill Coulter says Monday will feel like mid-40 degrees with the humidity.

Much of Ontario and southwestern Quebec are continuing to bake in high temperatures Monday as a heat dome lingers over the region.

Environment Canada issued a heat warning for the area on Saturday, saying hot and humid conditions will likely continue until Wednesday. Humidex values are expected to linger between 42 and 46 C.

The Toronto District School Board is warning of “uncomfortable conditions” in schools due to the extreme heat, advising students to wear light clothing, hats, sunscreen and to drink lots of water.

“Across the TDSB, while some schools are fully air conditioned and some are partially air conditioned, others have no air conditioning and the extreme heat will result in uncomfortable conditions,” the school board said in an email to parents on Sunday.

The email said closing schools due to extreme heat “is not an action typically taken by TDSB or other school boards across the province.”

Temperatures in Toronto are expected to reach a high of 36 C on Monday, Environment Canada said, with the humidex making it feel like 46 degrees.

The City of Toronto temporarily closed some of its outdoor pools on Sunday “to ensure staff health and safety” while adhering to provincial requirements when temperatures climb above 45 C.

The city says it is offering residents more than 500 spaces to cool down.

Overnight lows are forecast to stay between 22 to 25 C according to Environment Canada, “providing little relief from the heat.”

The dangerously high temperatures are expected to affect communities from southwestern Ontario and north to Sudbury and Timmins.

In Quebec, the hottest temperatures are expected to be felt from Montreal to Shawinigan and north to Abitibi.

People are encouraged to drink plenty of water to stay hydrated and be on alert for early signs of heat exhaustion.

This report by The Canadian Press was first published June 23, 2025.