Another warm month in the books and this time with readings extraordinarily far above average. And, while we did finally see our first, decent snow, there was only one.
The first five days of the month saw more typical temperatures, and indeed four of them were below average. Along with that, on the third we received a respectable 5.3 inches of snowfall.
From there, however, we warmed up and dried out. All but two of the final 26 days of the month saw above average temperatures. Twelve of those days saw record highs for their dates in the past 19 years.
On the 28th we did see one more, light snowfall (1.3 inches) but otherwise we were bone dry.
Thornton saw an overall average temperature for December 2025 of 42.1 degrees. This was far above our 19 year running average for the month of 31.5 degrees. It was also Thornton’s warmest December of the past 19 years by far. We saw our warmest temperature of 75.6 degrees on the 22nd and our coldest of 11.0 degrees on the 1st.
As measured at Denver International Airport, Denver saw an average temperature of 42.3 degrees for the month. This made the month the second warmest December ever recorded and was 11.1 degrees above their long-term December average. The city saw six high temperature records set or tied including record highs on Christmas Eve and Christmas Day.
In terms of precipitation, we did end up wetter than average. Thornton recorded 0.59 inches of liquid precipitation in our bucket, largely due to the snow on the 3rd. This total was above our running average for December of 0.44 inches.
Out at the airport, the Mile High City saw 0.33 inches of liquid precipitation. This was slightly below their long-term average for the month of 0.35 inches.
Thornton ended up with 6.6 inches of snowfall for the month. This was much appreciated after seeing no snow in September and October and only a minimal snow in November. It was, however, short of our 19-year average for December of 8.0 inches.
Denver matched our total with 6.6 inches of snowfall as measured at DIA as well. This was equal to the Mile High City’s 30-year average for the month.
Click here to view Thornton’s complete December 2025 climate summary report.
