Weather on August 31
Boulder, CO
55 Years of Data
Avg High
85°F
Avg Low
55°F
Warmest
1985
81°F avg
Coldest
1993
55°F avg
About This Date
August 31st in Boulder, CO typically brings warm summer weather, with average highs around 85°F and lows near 55°F — a 30°F daily swing. Over 55 years of records, the warmest August 31st was in 1985 (81°F average), while the coldest was 1993 (55°F) — a 26°F range across recorded history. Rain or other precipitation has occurred on about 29% of August 31st dates historically, with the wettest August 31st recording 0.56" of rain. The last decade has been 3.2°F warmer on this date compared to 20-30 years ago.
The last decade has been 3.2°F warmer on this date compared to 20-30 years ago.
Planning for August 31st in Boulder, CO? Stay hydrated and seek shade during peak afternoon hours.
Warming Trend
0.5°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 81° | 54° | 67° | — | — |
| 2024 | 90° | 55° | 72° | — | — |
| 2023 | 95° | 63° | 79° | — | — |
| 2022 | 91° | 61° | 76° | 0.05" | — |
| 2021 | 95° | 63° | 79° | — | — |
| 2020 | 72° | 46° | 59° | 0.08" | — |
| 2019 | 90° | 59° | 74° | — | — |
| 2018 | 88° | 61° | 74° | — | — |
| 2017 | 85° | 55° | 70° | 0.03" | — |
| 2016 | 78° | 51° | 65° | — | — |
| 2015 | 84° | 64° | 74° | 0.08" | — |
| 2014 | 81° | 52° | 66° | 0.38" | — |
| 2013 | 92° | 59° | 75° | 0.03" | — |
| 2012 | 93° | 56° | 74° | — | — |
| 2011 | 96° | 60° | 78° | 0.15" | — |
| 2010 | 83° | 54° | 68° | — | — |
| 2009 | 83° | 50° | 66° | — | — |
| 2008 | 88° | 55° | 71° | — | — |
| 2007 | 90° | 53° | 71° | — | — |
| 2006 | 86° | 59° | 73° | — | — |
| 2005 | 90° | 48° | 69° | — | — |
| 2004 | 85° | 50° | 67° | — | — |
| 2003 | 70° | 52° | 61° | 0.03" | — |
| 2002 | 92° | 55° | 73° | — | — |
| 2001 | 81° | 53° | 67° | — | — |
| 2000 | 77° | 49° | 63° | 0.08" | — |
| 1999 | 89° | 61° | 75° | 0.56" | — |
| 1998 | 84° | 60° | 72° | — | — |
| 1997 | 81° | 55° | 68° | — | — |
| 1996 | 87° | 49° | 68° | — | — |
| 1995 | 87° | 52° | 69° | — | — |
| 1994 | 73° | 56° | 64° | 0.18" | — |
| 1993coldest | 67° | 44° | 55° | — | — |
| 1992 | 74° | 45° | 59° | 0.13" | — |
| 1991 | 84° | 53° | 69° | — | — |
| 1990 | 85° | 62° | 73° | 0.3" | — |
| 1989 | 92° | 53° | 72° | — | — |
| 1988 | 90° | 63° | 76° | — | — |
| 1987 | 83° | 46° | 64° | — | — |
| 1986 | 76° | 55° | 65° | — | — |
| 1985warmest | 96° | 66° | 81° | — | — |
| 1984 | 88° | 55° | 71° | — | — |
| 1983 | 90° | 60° | 75° | — | — |
| 1982 | 90° | 59° | 74° | — | — |
| 1981 | 82° | 58° | 70° | — | — |
| 1980 | 79° | 48° | 63° | 0.23" | — |
| 1979 | 87° | 59° | 73° | — | — |
| 1978 | 84° | 52° | 68° | — | — |
| 1977 | 85° | 55° | 70° | 0.03" | — |
| 1976 | 80° | 55° | 68° | 0.3" | — |
| 1975 | 91° | 58° | 74° | — | — |
| 1974 | 79° | 48° | 63° | — | — |
| 1973 | 82° | 53° | 68° | — | — |
| 1972 | 80° | 56° | 68° | — | — |
| 1971 | 88° | 57° | 72° | — | — |
55 years of data from BOULDER MUNI AP