Weather on May 31
Boulder, CO
55 Years of Data
Avg High
74°F
Avg Low
47°F
Warmest
1984
74°F avg
Coldest
1979
43°F avg
About This Date
May 31st in Boulder, CO typically brings pleasant spring weather, with average highs around 74°F and lows near 47°F — a 27°F daily swing. Over 55 years of records, the warmest May 31st was in 1984 (74°F average), while the coldest was 1979 (43°F) — a 31°F range across recorded history. Rain or other precipitation has occurred on about 44% of May 31st dates historically, with the wettest May 31st recording 1.45" of rain. The last decade has been 1.2°F cooler on this date compared to 20-30 years ago.
The last decade has been 1.2°F cooler on this date compared to 20-30 years ago.
Planning for May 31st in Boulder, CO? Great weather for outdoor activities. Consider bringing rain gear or an umbrella.
Warming Trend
0.8°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 77° | 54° | 65° | — | — |
| 2024 | 70° | 50° | 60° | — | — |
| 2023 | 73° | 50° | 62° | — | — |
| 2022 | 59° | 41° | 50° | — | — |
| 2021 | 59° | 46° | 53° | 0.2" | — |
| 2020 | 86° | 55° | 71° | — | — |
| 2019 | 77° | 45° | 61° | — | — |
| 2018 | 88° | 54° | 71° | — | — |
| 2017 | 80° | 44° | 62° | 0.03" | — |
| 2016 | 70° | 49° | 59° | — | — |
| 2015 | 86° | 50° | 68° | — | — |
| 2014 | 76° | 48° | 62° | 0.18" | — |
| 2013 | 73° | 49° | 61° | — | — |
| 2012 | 73° | 43° | 58° | — | — |
| 2011 | 77° | 44° | 61° | — | — |
| 2010 | 79° | 43° | 61° | — | — |
| 2009 | 75° | 51° | 63° | — | — |
| 2008 | 79° | 49° | 64° | — | — |
| 2007 | 77° | 42° | 60° | — | — |
| 2006 | 77° | 45° | 61° | 0.08" | — |
| 2005 | 69° | 45° | 57° | 0.13" | — |
| 2004 | 75° | 40° | 57° | — | — |
| 2003 | 79° | 55° | 67° | 0.28" | — |
| 2002 | 89° | 58° | 73° | — | — |
| 2001 | 75° | 43° | 59° | — | — |
| 2000 | 76° | 52° | 64° | 0.08" | — |
| 1999 | 73° | 50° | 62° | 0.05" | — |
| 1998 | 84° | 48° | 66° | — | — |
| 1997 | 81° | 44° | 62° | — | — |
| 1996 | 74° | 45° | 59° | — | — |
| 1995 | 70° | 39° | 54° | 0.1" | — |
| 1994 | 77° | 54° | 65° | 0.03" | — |
| 1993 | 81° | 47° | 64° | — | — |
| 1992 | 58° | 41° | 49° | 0.3" | — |
| 1991 | 72° | 49° | 60° | 0.58" | — |
| 1990 | 72° | 40° | 56° | 0.43" | — |
| 1989 | 62° | 44° | 53° | 1.45" | — |
| 1988 | 70° | 50° | 60° | 0.05" | — |
| 1987 | 83° | 46° | 64° | — | — |
| 1986 | 77° | 46° | 62° | — | — |
| 1985 | 71° | 43° | 57° | 0.03" | — |
| 1984warmest | 86° | 63° | 74° | 0.23" | — |
| 1983 | 54° | 35° | 44° | 1.14" | — |
| 1982 | 64° | 42° | 53° | 0.51" | — |
| 1981 | 75° | 51° | 63° | 0.36" | — |
| 1980 | 81° | 43° | 62° | — | — |
| 1979coldest | 46° | 39° | 43° | 1.14" | — |
| 1978 | 71° | 44° | 58° | 0.41" | — |
| 1977 | 80° | 47° | 63° | — | — |
| 1976 | 75° | 43° | 59° | 0.05" | — |
| 1975 | 64° | 44° | 54° | 0.05" | — |
| 1974 | 77° | 49° | 63° | — | — |
| 1973 | 78° | 41° | 60° | — | — |
| 1972 | 83° | 47° | 65° | — | — |
| 1971 | 69° | 42° | 56° | — | — |
55 years of data from BOULDER MUNI AP