Christmas records in peril as holiday heat blankets North America

The strong start to winter that charged across North America will find itself on shaky ground to close out the final days of December.

A formidable ridge of high pressure building into the holidays will send temperatures soaring significantly above normal for parts of Canada and much of the U.S.

Readings may climb more than 5 degrees above seasonal in Ontario, while conditions will feel like late August or early September in parts of the U.S.

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Forecasters will monitor the progress of a large ridge of high pressure sliding into the central U.S. leading up to Christmas on Thursday.

Unusually warm temperatures south of the border will occasionally surge into the southern reaches of Canada in the days to come. Ontario will find itself on the dividing line between Arctic air to the north and unseasonable warmth to the south.

We’ll see a wide range in temperatures across Ontario and Quebec by Christmas Day. This is a tricky forecast for many communities, as a relatively tiny shift in that dividing line could significantly affect the day’s high temperatures.

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Much of Ontario will see daytime high temperatures on Christmas come in 5+ degrees above seasonal. Even a high of -3°C in Ottawa is just a touch above seasonal for Dec. 25.

If the warm temperatures arrive during the evening, some neighbourhoods that saw a blanket of snow outside on Christmas morning may close out the day with bare ground.

For context, the warmest Christmas on record in Toronto was 15.7°C in 1982. Timmins climbed well above the freezing mark in 2023 when the community hit 3.9°C, cementing that day two years ago as one of Ontario's warmest-ever Christmases.

Some U.S. cities face their all-time warmest Christmases

While Ontario's records are safe for another year, history is in the making down south.

Readings as much as 15 degrees above seasonal will threaten daily records throughout the U.S. Many spots will likely end the day having witnessed one of their top-five warmest Christmases on record.

A forecast high of 25°C in Oklahoma City would be the highest temperature ever observed there on Christmas, beating the previous record high of 22.8°C back in 2016. The city’s average high on Dec. 25 comes in around 9.4°C.

Similarly, folks in St. Louis and Kansas City may also break their Dec. 25 record highs by several degrees. That’s no small feat when records in St. Louis stretch all the way back to 1874.

Header image created using graphics and imagery from Canva.

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