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Environment Canada heat warnings remain in effect from Ontario to Newfoundland

Daytime temperatures from Windsor, Ontario, to St. John's, Newfoundland, are going to remain hot a little longer. Environment Canada has several heat warnings in effect this morning, along a 2,400-kilometre stretch of southeastern Canada.
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The sun rises over the Toronto skyline on Tuesday June 24, 2025. THE CANADIAN PRESS/Frank Gunn

Daytime temperatures from Windsor, Ontario, to St. John's, Newfoundland, are going to remain hot a little longer.

Environment Canada has several heat warnings in effect this morning, along a 2,400-kilometre stretch of southeastern Canada.

The warnings forecast daytime highs in some areas between 31 and 34 degrees Celsius -- with a humidex of 37 to 42.

As with any heat warning, it is recommended that people watch for the early signs of heat exhaustion and check in with vulnerable family and friends to ensure their well-being.

For residents in Southern Ontario and southern Quebec, the heat wave is expected to start cooling off later today or this evening, while farther east the warmer weather will likely linger into Friday.

There was also one heat warning posted for the Northwest Territories -- in the Hay River region -- with highs forecast to reach 28 to 31.

This report by The Canadian Press was first published July 17, 2025.

The Canadian Press