Weather on December 17
Longmont, CO
55 Years of Data
Avg High
44°F
Avg Low
15°F
Warmest
2025
51°F avg
Coldest
1989
8°F avg
About This Date
December 17th in Longmont, CO typically brings chilly winter weather, with average highs around 44°F and lows near 15°F — a 29°F daily swing. Over 55 years of records, the warmest December 17th was in 2025 (51°F average), while the coldest was 1989 (8°F) — a 43°F range across recorded history. Precipitation has occurred on 16% of recorded December 17th dates, with snow falling 15% of the time (heaviest snowfall: 5.2"). The last decade has been 3.2°F warmer on this date compared to 20-30 years ago.
The last decade has been 3.2°F warmer on this date compared to 20-30 years ago.
Planning for December 17th in Longmont, CO? Bring layers as temperatures can vary throughout the day.
Warming Trend
1.4°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025warmest | 69° | 33° | 51° | — | — |
| 2024 | 47° | 25° | 36° | — | — |
| 2023 | 58° | 23° | 40° | — | — |
| 2022 | 36° | 9° | 22° | — | — |
| 2021 | 45° | 20° | 32° | — | — |
| 2020 | 46° | 15° | 31° | — | — |
| 2019 | 35° | 10° | 23° | — | — |
| 2018 | 55° | 20° | 37° | — | — |
| 2017 | 50° | 31° | 40° | 0.03" | — |
| 2016 | 26° | -7° | 10° | 1.02" | 5.2" |
| 2015 | 27° | 8° | 17° | — | — |
| 2014 | 46° | 20° | 33° | — | — |
| 2013 | 63° | 31° | 47° | — | — |
| 2012 | 46° | 24° | 35° | — | — |
| 2011 | 45° | 20° | 32° | — | — |
| 2010 | 32° | 20° | 26° | 0.1" | 1.1" |
| 2009 | 53° | 32° | 43° | — | — |
| 2008 | 40° | 1° | 20° | — | — |
| 2007 | 54° | 19° | 36° | — | — |
| 2006 | 38° | 24° | 31° | — | — |
| 2005 | 20° | 11° | 15° | 0.1" | 2" |
| 2004 | 48° | 26° | 37° | — | — |
| 2003 | 46° | 13° | 29° | — | — |
| 2002 | 62° | 26° | 44° | — | — |
| 2001 | 36° | 5° | 20° | — | — |
| 2000 | 30° | 13° | 21° | — | — |
| 1999 | 60° | 31° | 45° | — | — |
| 1998 | 45° | 16° | 30° | — | — |
| 1997 | 55° | 16° | 35° | — | — |
| 1996 | 39° | -12° | 14° | 0.38" | 1.6" |
| 1995 | 43° | 19° | 31° | — | — |
| 1994 | 53° | 15° | 34° | — | — |
| 1993 | 34° | 8° | 21° | — | — |
| 1992 | 29° | -4° | 12° | — | — |
| 1991 | 63° | 19° | 41° | — | — |
| 1990 | 49° | 24° | 36° | 0.13" | 1" |
| 1989coldest | 22° | -6° | 8° | 0.13" | 2" |
| 1988 | 33° | -2° | 16° | — | — |
| 1987 | 33° | 4° | 18° | — | — |
| 1986 | 48° | 20° | 34° | — | — |
| 1985 | 43° | 13° | 28° | — | — |
| 1984 | 36° | 16° | 26° | — | — |
| 1983 | 31° | 9° | 20° | — | — |
| 1982 | 58° | 24° | 41° | — | — |
| 1981 | 42° | 9° | 25° | 0.1" | 1" |
| 1980 | 67° | 30° | 48° | — | — |
| 1979 | 26° | 11° | 18° | — | — |
| 1978 | 33° | 10° | 22° | — | — |
| 1977 | 42° | 21° | 32° | — | — |
| 1976 | 63° | 21° | 42° | — | — |
| 1975 | 31° | 9° | 20° | 0.41" | 2.5" |
| 1974 | 43° | 16° | 29° | — | — |
| 1973 | 52° | 25° | 38° | — | — |
| 1972 | 35° | -9° | 13° | — | — |
| 1971 | 37° | 11° | 24° | — | — |
55 years of data from LONGMONT 2 ESE