When will Canada see its last 30°C of the year?

Canada just saw its first -10°C of the season. The heart of summertime is in the rearview mirror for much of the country, with most major cities past the average date for the last 30°C temperature of the season.

Despite the cooldown, summer-like heat can still make an autumnal appearance, and this year looks to be no exception. Warmer-than-normal readings over the next week may still send some communities inching into the 30s.

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The heat's been on since Lytton, B.C., marked Canada's first 30-degree temperature of the year back on April 20.

While things have cooled off lately, forecasters continue to see increased odds of above-seasonal temperatures for much of Canada over the next five to seven days.

While the bulk of the heat will be centred stateside, where they'll likely see a near-historic ridge for this time of year, the warmer temperatures will make their way well into Canada.

The greatest potential for additional 30-degree heat in the coming days will arrive in British Columbia on Thursday and Friday. Temperatures will approach 30°C throughout the southern B.C. Interior, including Lytton, Kamloops, Osoyoos, and Ashcroft.

When do we typically see our last 30-degree temperatures, and how late in the year are they possible?

Edmonton is usually out of the deep summer heat by the beginning of August, followed by communities in northern Ontario, southern Quebec, and the Maritimes later in the month.

Early September is the average final 30-degree day of the year for southern B.C. and the southern Prairies, with Toronto rounding out the pack with an average date of Sept. 10.

Those are just averages, of course, and it's possible to get fairly hot fairly late in the year. The latest such reading on record occurred in Maple Creek, Sask., way back on Oct. 25, 1924. That day more than a century ago saw the mercury rise to an impressive 30.6°C.

In fact, four of the past five years have seen temperatures somewhere in Canada crack into the 30s during the month of October, including New Brunswick in 2025, Ontario in 2023, B.C. in 2022, and Saskatchewan in 2021.