Stifling heat forecast in Ontario, Quebec, Atlantic provinces and parts of B.C.

By Canadian Press on August 11, 2025.

Another day of punishing heat and humidity is expected to hit Ontario, Quebec and the four Atlantic provinces.

A heat warning from Environment Canada remains in effect for all of southern Ontario, stretching north past Lake Huron and Georgian Bay and east through southern Quebec.

Expected daytime highs could reach 35 degrees Celsius in some parts, with the humidex at or near 40 C.

Hot conditions are also washing over Atlantic Canada, with most of New Brunswick, Nova Scotia, Prince Edward Island and parts of Newfoundland and Labrador also under a heat warning.

Daytime highs in the region are forecast to reach around 30 degrees, with New Brunswick expecting that humid conditions will make it feel like 42 C.

In British Columbia, heat warnings are also in place for most of Vancouver Island, the Sunshine Coast, as well as southern B.C’s Fraser Canyon, South Thompson and South Okanagan areas.

Environment Canada recommends monitoring for signs of heat exhaustion, as well as drinking water in these conditions.