December 2025 Summary

A very cold and snowy December

During the first half of the month the temperature was very cold, with many daily lows more than ten degrees below average.  The second half was warmer and actually a bit above average.  However, with the cold start, the overall temperature was a bit more than 3 degrees below average, making it the second coldest December in the last 20 years (the coldest was 2017).

There was also an interesting spike in the temperature early in the morning of the 29th where it went from 0.8°C to 8.9°C in an hour, then down to 4.8°C an hour later and well below zero a few hours after that.

The precipitation for December was going along mostly average before the almost 50 mm on the 28th pushed the total to 113.2 mm, well above the average of 72.1 mm.

There was a little less snowfall this month than the previous month, but the 54.5 cm was still well above the average of 30.7 cm and the snowiest December since 2008.  With two months of very high snowfall, the total so far this snowfall season of 113.5 cm is well over twice the average of 41.8 cm.  Also, since we haven’t had any mid-winter thaws, most of that snow is still around.

Summary for December 2025:

Maximum Temperature 8.9°C
Minimum Temperature -23.1°C
Average Daily High Temperature -0.7°C (Long term average 0.7°C)
Average Daily Low Temperature -11.1°C (Long term average -5.9°C)
Total Precipitation 113.2 mm (Long term average 72.1 mm)

(Long term averages based on 1998-2024 data from the Soulis Memorial Weather Station at the University of Waterloo)