Weather on April 21
Boulder, CO
55 Years of Data
Avg High
63°F
Avg Low
37°F
Warmest
1989
70°F avg
Coldest
2021
30°F avg
About This Date
April 21st in Boulder, CO typically brings mild spring weather, with average highs around 63°F and lows near 37°F — a 26°F daily swing. Over 55 years of records, the warmest April 21st was in 1989 (70°F average), while the coldest was 2021 (30°F) — a 40°F range across recorded history. Precipitation has occurred on 24% of recorded April 21st dates, with snow falling 5% of the time (heaviest snowfall: 2"). Temperatures on this date have remained relatively stable over the past several decades.
Temperatures on this date have remained relatively stable over the past several decades.
Planning for April 21st in Boulder, CO? Great weather for outdoor activities.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 70° | 39° | 54° | — | — |
| 2024 | 63° | 32° | 47° | — | — |
| 2023 | 52° | 32° | 42° | — | — |
| 2022 | 79° | 45° | 62° | — | — |
| 2021coldest | 32° | 28° | 30° | — | — |
| 2020 | 66° | 39° | 53° | — | — |
| 2019 | 68° | 45° | 56° | — | — |
| 2018 | 41° | 32° | 37° | — | — |
| 2017 | 53° | 39° | 46° | 0.91" | — |
| 2016 | 65° | 37° | 51° | — | — |
| 2015 | 67° | 33° | 50° | — | — |
| 2014 | 66° | 41° | 54° | — | — |
| 2013 | 63° | 33° | 48° | — | — |
| 2012 | 75° | 48° | 62° | — | — |
| 2011 | 70° | 37° | 53° | 0.51" | — |
| 2010 | 59° | 43° | 51° | 0.08" | — |
| 2009 | 75° | 42° | 59° | — | — |
| 2008 | 68° | 32° | 50° | — | — |
| 2007 | 65° | 43° | 54° | — | — |
| 2006 | 74° | 36° | 55° | — | — |
| 2005 | 60° | 31° | 45° | 0.25" | — |
| 2004 | 59° | 35° | 47° | 0.51" | — |
| 2003 | 61° | 33° | 47° | — | — |
| 2002 | 56° | 32° | 44° | — | — |
| 2001 | 59° | 34° | 46° | 0.05" | — |
| 2000 | 75° | 36° | 55° | — | — |
| 1999 | 66° | 44° | 55° | 0.03" | — |
| 1998 | 58° | 34° | 46° | — | — |
| 1997 | 68° | 48° | 58° | — | — |
| 1996 | 52° | 30° | 41° | — | — |
| 1995 | 41° | 32° | 37° | 1.3" | 0.9" |
| 1994 | 77° | 38° | 57° | — | — |
| 1993 | 62° | 27° | 44° | — | — |
| 1992 | 67° | 30° | 48° | — | — |
| 1991 | 53° | 39° | 46° | 0.3" | — |
| 1990 | 72° | 41° | 56° | — | — |
| 1989warmest | 88° | 53° | 70° | — | — |
| 1988 | 71° | 51° | 61° | — | — |
| 1987 | 59° | 25° | 42° | 0.05" | 0.2" |
| 1986 | 65° | 40° | 52° | 0.05" | — |
| 1985 | 60° | 37° | 49° | — | — |
| 1984 | 44° | 31° | 37° | 0.81" | 2" |
| 1983 | 54° | 43° | 48° | 1.63" | — |
| 1982 | 54° | 18° | 36° | — | — |
| 1981 | 73° | 46° | 60° | — | — |
| 1980 | 83° | 49° | 66° | — | — |
| 1979 | 72° | 36° | 54° | — | — |
| 1978 | 62° | 31° | 46° | — | — |
| 1977 | 60° | 29° | 44° | — | — |
| 1976 | 66° | 41° | 54° | — | — |
| 1975 | 61° | 36° | 48° | — | — |
| 1974 | 60° | 37° | 49° | — | — |
| 1973 | 52° | 32° | 42° | — | — |
| 1972 | 61° | 31° | 46° | — | — |
| 1971 | 61° | 37° | 49° | — | — |
55 years of data from BOULDER MUNI AP