Weather on December 21
Boise, ID
55 Years of Data
About This Date
December 21st in Boise, ID typically brings cold winter weather, with average highs around 38°F and lows near 25°F. Over 55 years of records, the warmest December 21st was in 2020 (50°F average), while the coldest was 1990 (-13°F) — a 63°F range across recorded history. Precipitation has occurred on 45% of recorded December 21st dates, with snow falling 15% of the time (heaviest snowfall: 3.1"). The last decade has been 4.9°F warmer on this date compared to 20-30 years ago.
The last decade has been 4.9°F warmer on this date compared to 20-30 years ago.
Planning for December 21st in Boise, ID? Bundle up with warm layers and protect extremities from the cold. Consider bringing rain gear or an umbrella.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 45° | 36° | 40° | 2.36" | — |
| 2024 | 41° | 32° | 37° | 0.03" | — |
| 2023 | 37° | 32° | 35° | 0.03" | — |
| 2022 | 38° | 17° | 28° | 0.03" | — |
| 2021 | 42° | 25° | 34° | — | — |
| 2020warmest | 58° | 43° | 50° | — | — |
| 2019 | 50° | 40° | 45° | — | — |
| 2018 | 41° | 29° | 35° | 0.03" | — |
| 2017 | 35° | 22° | 29° | — | — |
| 2016 | 30° | 11° | 21° | — | — |
| 2015 | 45° | 34° | 39° | 0.28" | — |
| 2014 | 47° | 40° | 43° | 1.93" | — |
| 2013 | 30° | 21° | 26° | 0.05" | 0.2" |
| 2012 | 46° | 39° | 43° | — | — |
| 2011 | 42° | 18° | 30° | — | — |
| 2010 | 42° | 28° | 35° | — | — |
| 2009 | 48° | 34° | 41° | 0.03" | — |
| 2008 | 36° | 24° | 30° | 0.28" | 2.5" |
| 2007 | 35° | 22° | 28° | — | — |
| 2006 | 28° | 19° | 24° | 0.23" | 0.9" |
| 2005 | 49° | 32° | 40° | 0.71" | — |
| 2004 | 36° | 20° | 28° | — | — |
| 2003 | 45° | 30° | 37° | 0.05" | — |
| 2002 | 42° | 33° | 38° | 0.28" | — |
| 2001 | 36° | 25° | 30° | — | — |
| 2000 | 44° | 29° | 36° | — | — |
| 1999 | 47° | 25° | 36° | — | — |
| 1998 | 13° | -2° | 5° | — | — |
| 1997 | 37° | 22° | 29° | — | — |
| 1996 | 35° | 18° | 26° | 0.05" | 0.3" |
| 1995 | 36° | 24° | 30° | — | — |
| 1994 | 37° | 26° | 32° | — | — |
| 1993 | 31° | 26° | 28° | — | — |
| 1992 | 36° | 31° | 33° | — | — |
| 1991 | 34° | 17° | 25° | — | — |
| 1990coldest | -3° | -23° | -13° | 0.03" | 0.1" |
| 1989 | 46° | 17° | 32° | — | — |
| 1988 | 39° | 29° | 34° | 0.58" | 3.1" |
| 1987 | 42° | 31° | 36° | — | — |
| 1986 | 27° | 21° | 24° | — | — |
| 1985 | 13° | -3° | 5° | — | — |
| 1984 | 16° | -1° | 8° | 0.1" | 0.3" |
| 1983 | 14° | -8° | 3° | 0.03" | — |
| 1982 | 52° | 41° | 46° | 0.08" | — |
| 1981 | 45° | 32° | 38° | 0.84" | — |
| 1980 | 47° | 27° | 37° | 0.23" | — |
| 1979 | 46° | 36° | 41° | 0.43" | — |
| 1978 | 41° | 29° | 35° | 0.05" | 0.2" |
| 1977 | 35° | 23° | 29° | — | — |
| 1976 | 35° | 8° | 22° | — | — |
| 1975 | 21° | 17° | 19° | — | — |
| 1974 | 53° | 32° | 43° | — | — |
| 1973 | 48° | 38° | 43° | 0.33" | — |
| 1972 | 51° | 46° | 49° | — | — |
| 1971 | 44° | 37° | 41° | — | — |
Boise, ID Temperature Range by Month
Average monthly highs and lows. The shaded band shows the typical daily temperature range.
Boise, ID Monthly Precipitation
Average rainfall and snowfall per month, in inches.
Boise, ID Daily Temperature Calendar
Average daily high temperature for every day of the year. Each cell is the climatological mean for that calendar day across 55 years of NOAA data.
Best Time to Visit Boise, ID
Boise, ID has no months that meet our "pleasant" threshold — every season has tradeoffs.