Weather on April 21
Boise, ID
55 Years of Data
Avg High
65°F
Avg Low
41°F
Warmest
2009
69°F avg
Coldest
2008
37°F avg
About This Date
April 21st in Boise, ID typically brings mild spring weather, with average highs around 65°F and lows near 41°F. Over 55 years of records, the warmest April 21st was in 2009 (69°F average), while the coldest was 2008 (37°F) — a 32°F range across recorded history. Rain or other precipitation has occurred on about 27% of April 21st dates historically, with the wettest April 21st recording 1.47" of rain. The last decade has been 3.5°F warmer on this date compared to 20-30 years ago.
The last decade has been 3.5°F warmer on this date compared to 20-30 years ago.
Planning for April 21st in Boise, ID? Great weather for outdoor activities.
Warming Trend
0.6°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 61° | 38° | 49° | — | — |
| 2024 | 62° | 46° | 54° | — | — |
| 2023 | 53° | 39° | 46° | 0.2" | — |
| 2022 | 57° | 43° | 50° | 0.25" | — |
| 2021 | 66° | 38° | 52° | — | — |
| 2020 | 73° | 42° | 58° | — | — |
| 2019 | 67° | 48° | 57° | — | — |
| 2018 | 70° | 44° | 57° | — | — |
| 2017 | 59° | 34° | 46° | — | — |
| 2016 | 87° | 52° | 69° | — | — |
| 2015 | 76° | 45° | 60° | — | — |
| 2014 | 75° | 42° | 59° | — | — |
| 2013 | 64° | 38° | 51° | — | — |
| 2012 | 82° | 50° | 66° | — | — |
| 2011 | 50° | 35° | 43° | 1.47" | — |
| 2010 | 60° | 47° | 53° | 0.08" | — |
| 2009warmest | 86° | 51° | 69° | — | — |
| 2008coldest | 49° | 26° | 37° | — | — |
| 2007 | 63° | 38° | 50° | — | — |
| 2006 | 71° | 47° | 59° | — | — |
| 2005 | 61° | 43° | 52° | 1.04" | — |
| 2004 | 52° | 39° | 45° | 0.38" | — |
| 2003 | 67° | 51° | 59° | 0.05" | — |
| 2002 | 64° | 33° | 49° | — | — |
| 2001 | 55° | 40° | 47° | 0.03" | — |
| 2000 | 67° | 44° | 55° | — | — |
| 1999 | 54° | 34° | 44° | — | — |
| 1998 | 77° | 47° | 62° | — | — |
| 1997 | 59° | 38° | 48° | — | — |
| 1996 | 54° | 30° | 42° | — | — |
| 1995 | 60° | 36° | 48° | — | — |
| 1994 | 79° | 55° | 67° | — | — |
| 1993 | 70° | 37° | 53° | — | — |
| 1992 | 61° | 46° | 53° | 0.33" | — |
| 1991 | 70° | 47° | 58° | — | — |
| 1990 | 64° | 47° | 55° | 0.46" | — |
| 1989 | 76° | 49° | 62° | — | — |
| 1988 | 60° | 43° | 51° | 0.05" | — |
| 1987 | 78° | 42° | 60° | — | — |
| 1986 | 83° | 49° | 66° | — | — |
| 1985 | 48° | 32° | 40° | 0.99" | — |
| 1984 | 59° | 38° | 48° | — | — |
| 1983 | 63° | 44° | 53° | — | — |
| 1982 | 63° | 30° | 46° | — | — |
| 1981 | 59° | 45° | 52° | 0.46" | — |
| 1980 | 68° | 51° | 60° | — | — |
| 1979 | 70° | 35° | 52° | — | — |
| 1978 | 49° | 34° | 41° | 0.03" | — |
| 1977 | 76° | 48° | 62° | — | — |
| 1976 | 56° | 30° | 43° | — | — |
| 1975 | 65° | 39° | 52° | — | — |
| 1974 | 63° | 31° | 47° | — | — |
| 1973 | 62° | 37° | 50° | — | — |
| 1972 | 60° | 41° | 51° | 0.2" | — |
| 1971 | 59° | 43° | 51° | — | — |
55 years of data from BOISE AIR TERMINAL