We couldn’t ask for a stronger signal of above-normal temperatures heading into the final week of December, covering Christmas through New Year’s. After a stretch of below-seasonal temperatures leading up to the holiday, this warm spell will give many Canadians a chance to thaw out.
To put it bluntly, winter will be taking a vacation for the final week of December. Of course, this is just a temperature forecast—so be sure to check out our other content for details on active weather during this period.
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In fact, looking at the models, not a single part of North America is forecast to experience any significant below-seasonal temperatures. Every teleconnection (those large-scale patterns that dictate weather flow) points to an unrelenting surge of mild air across the continent.
Temperature trend for the last week of December 2024
The power of modern computer models
Computer models have come a long way in predicting temperature trends in the 5- to 10-day range. They can now reliably analyze where ridges (warm air) and troughs (cold air) will set up across North America, giving us confidence in the patterns we see.
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This article will start at the highest levels of the atmosphere, where the polar vortex likes to hang out, and work our way down to what we actually experience at the surface.
Christmas Day 2024 Temperature Anomalies
These temperature projections for Christmas highlight well-above seasonal temperatures across the Prairies and Northern Canada, while some stubborn remnant Arctic air is draped across eastern Ontario to Labrador.
Christmas Day 2024 forecast conditions
The Tropopause – Where the action begins (10-12 km up)
Let’s start way up—at the boundary where air from the stratosphere starts to mix with the troposphere, the layer where we live. This is a critical marker for tracking lobes of Arctic air.
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On maps, the purples and blues represent extremely cold air spilling south from the Arctic.
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The yellows and reds are milder air masses originating from lower latitudes.
Tropopause: All eyes will be on the Pacific Ocean, poised to flood mild air across North America.
All eyes will be on the Pacific Ocean, poised to flood mild air across North America. This inflow of warmth is the big story, and as we move lower, you’ll see how it interacts with the jet stream to build ridges (warm air) and troughs (cold air).
Slicing the atmosphere in Half – 500 hPa (5-6 km)
Imagine the atmosphere as a layered cake. If we slice it at the 500 hPa level, we’re cutting right through the middle of the troposphere. This gives us a perfect cross-section of the atmosphere, and it’s one of the most valuable slices for meteorologists.
Upper level sketch – final week of December, Canada temperatures 2024
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What’s revealed? Strong zonal flow (west-to-east winds) and unusually high heights for this time of year, especially over regions like Hudson Bay.
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High heights mean warm air aloft, a key signal for mild weather.
850 hPa – Just above the surface (1.5 km)
Dropping down to 850 hPa, we’re now just 1,500 metres above the ground. This level is critical because it reveals how air masses behave with minimal influence from surface friction or terrain.
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Forecast departures from normal temperatures at this level show just how far above seasonal this mild air mass will be.
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Air masses at 850 hPa are a reliable indicator of temperature trends that eventually make their way to the surface.
850 HPA temperature anomaly
The surface – What you’ll actually experience
If you’ve made it this far, this is probably what you care about most: what it means for you on the ground.
Yes, “above seasonal” sounds warm, but let’s be clear—late December is still chilly across much of Canada.
WEATHERBELL: Surface temperature anomaly Dec. 2024
For context:
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In places where -20°C is normal, like Hudson Bay, above-seasonal air might still hover near 0°C.
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There’s even the possibility that the 0-degree line arcs across Hudson Bay at times—a region that typically sees harsh winter conditions this time of year.
So while it might not be beach weather, compared to what’s typical for late December, this “Torch-mas” will feel like a winter vacation for much of Canada. Note that the temperature anomalies around the edge of the ‘torch pattern’ are under 5°C above normal, meaning that winter weather is still possible.
The combination of strong signals from the atmosphere, Pacific-driven warmth, and reliable model guidance gives us high confidence in this forecast. Enjoy the thaw while it lasts—winter is always waiting to make a comeback.
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