Wild temperature swing could end with snow in parts of Central Canada

A pleasant warmup through the first half of the week will crash into a November-like chill for Ontario and Quebec, complete with snow and frost for some.

Central Canada is going to ride a temperature rollercoaster into the Thanksgiving weekend.

Folks across Ontario and Quebec will endure a wild temperature swing this week with comfortable temperatures plummeting into a November-like chill, complete with a chance for snow and frost in some areas.


DON’T MISS: Canada’s October outlook: what you can expect this month


The week begins with a gradual warming trend across Central Canada, peaking on Wednesday as temperatures reach or exceed 20°C in southern Ontario and Quebec, with upper teens to near 20°C in the National Capital Region.

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Comfortable conditions won’t last long, though, as a cold front plows into the region.

This potent front will track across Ontario and Quebec on Thursday, producing showers as gusty winds usher in a dramatic drop in temperatures. Wet snow is even likely for northern Ontario by early Thursday as temperatures dip into the low- to mid-single digits.

Wet snow will attempt to spread across northeastern Ontario later in the day Thursday before the cold front slides across southern sections. There's even a chance some flakes will mix in near Blue Mountain as we approach the weekend.

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Overnight lows this week will bring a likely frost in some areas, so make sure to protect your plants. The risk will become more widespread at the end of the week.

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Friday is going to be the coldest day many of us have seen in months. November-like weather arrives to end the week with high temperatures remaining in the single digits for much of the region.

If Toronto only reaches 9°C on Friday, it’ll be the city’s first single-digit high temperature in 169 days—our last daytime high below 10 degrees was a chilly 4.7°C reading on April 27th.

Chilly weather will remain for the start of the long weekend, but temperatures should rebound somewhat to near seasonal as it progresses. However, there is the potential for a couple days of milder weather during the following week.

Will the pattern shift in October?

As October progresses, there are several signals in the global pattern that support a shift in the cool pattern, which would allow the warmer than normal weather in the west to spread back east into Eastern Canada, according to Dr. Doug Gillham, a meteorologist at The Weather Network.

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“However, our forecast confidence for the middle and end of October is lower than normal,” said Gillham in The Weather Network's October outlook.

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But, we still think that the second half of October will bring periods of milder weather, but we are also concerned that the early pattern will continue to show up at times during the latter portion of the month.

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Check back for the latest on conditions across Ontario and Quebec.