Weather on May 20
Boulder, CO
55 Years of Data
Avg High
71°F
Avg Low
45°F
Warmest
2006
75°F avg
Coldest
2019
37°F avg
About This Date
May 20th in Boulder, CO typically brings pleasant spring weather, with average highs around 71°F and lows near 45°F — a 26°F daily swing. Over 55 years of records, the warmest May 20th was in 2006 (75°F average), while the coldest was 2019 (37°F) — a 38°F range across recorded history. Precipitation has occurred on 33% of recorded May 20th dates, with snow falling 2% of the time. The last decade has been 7.3°F cooler on this date compared to 20-30 years ago.
The last decade has been 7.3°F cooler on this date compared to 20-30 years ago.
Planning for May 20th in Boulder, CO? Great weather for outdoor activities. Consider bringing rain gear or an umbrella.
Cooling Trend
1.3°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 68° | 37° | 53° | — | — |
| 2024 | 64° | 43° | 53° | — | — |
| 2023 | 66° | 48° | 57° | — | — |
| 2022 | 41° | 32° | 37° | — | — |
| 2021 | 78° | 42° | 60° | 0.05" | — |
| 2020 | 88° | 54° | 71° | — | — |
| 2019coldest | 41° | 32° | 37° | — | — |
| 2018 | 54° | 41° | 47° | — | — |
| 2017 | 63° | 30° | 46° | — | — |
| 2016 | 78° | 46° | 62° | — | — |
| 2015 | 43° | 35° | 39° | 0.81" | — |
| 2014 | 78° | 51° | 65° | — | — |
| 2013 | 65° | 46° | 55° | 0.15" | — |
| 2012 | 73° | 38° | 55° | — | — |
| 2011 | 61° | 34° | 47° | 1.32" | — |
| 2010 | 69° | 44° | 57° | — | — |
| 2009 | 82° | 52° | 67° | — | — |
| 2008 | 81° | 47° | 64° | — | — |
| 2007 | 81° | 47° | 64° | — | — |
| 2006warmest | 87° | 62° | 75° | — | — |
| 2005 | 90° | 54° | 72° | — | — |
| 2004 | 77° | 51° | 64° | — | — |
| 2003 | 57° | 39° | 48° | — | — |
| 2002 | 66° | 46° | 56° | — | — |
| 2001 | 76° | 34° | 55° | 0.18" | 0.2" |
| 2000 | 68° | 47° | 57° | 0.05" | — |
| 1999 | 75° | 51° | 63° | 0.48" | — |
| 1998 | 76° | 46° | 61° | — | — |
| 1997 | 80° | 41° | 61° | — | — |
| 1996 | 75° | 43° | 59° | — | — |
| 1995 | 66° | 46° | 56° | 0.05" | — |
| 1994 | 79° | 49° | 64° | — | — |
| 1993 | 74° | 44° | 59° | 0.08" | — |
| 1992 | 84° | 50° | 67° | — | — |
| 1991 | 71° | 55° | 63° | — | — |
| 1990 | 69° | 44° | 57° | — | — |
| 1989 | 79° | 39° | 59° | — | — |
| 1988 | 54° | 40° | 47° | 1.45" | — |
| 1987 | 62° | 51° | 57° | 0.48" | — |
| 1986 | 82° | 46° | 64° | 0.03" | — |
| 1985 | 59° | 46° | 53° | 0.84" | — |
| 1984 | 91° | 45° | 68° | — | — |
| 1983 | 58° | 40° | 49° | 0.33" | — |
| 1982 | 68° | 45° | 56° | 0.38" | — |
| 1981 | 65° | 42° | 53° | — | — |
| 1980 | 76° | 39° | 57° | — | — |
| 1979 | 76° | 45° | 60° | 0.08" | — |
| 1978 | 70° | 47° | 58° | — | — |
| 1977 | 63° | 42° | 52° | 0.15" | — |
| 1976 | 74° | 50° | 62° | — | — |
| 1975 | 78° | 42° | 60° | — | — |
| 1974 | 84° | 51° | 68° | — | — |
| 1973 | 80° | 59° | 70° | — | — |
| 1972 | 79° | 47° | 63° | 0.03" | — |
| 1971 | 69° | 40° | 54° | — | — |
55 years of data from BOULDER MUNI AP