Weather on May 18
Boulder, CO
55 Years of Data
Avg High
73°F
Avg Low
46°F
Warmest
1996
70°F avg
Coldest
1971
43°F avg
About This Date
May 18th in Boulder, CO typically brings pleasant spring weather, with average highs around 73°F and lows near 46°F — a 27°F daily swing. Over 55 years of records, the warmest May 18th was in 1996 (70°F average), while the coldest was 1971 (43°F) — a 27°F range across recorded history. Precipitation has occurred on 31% of recorded May 18th dates, with snow falling 2% of the time (heaviest snowfall: 5.3"). The last decade has been 4.3°F cooler on this date compared to 20-30 years ago.
The last decade has been 4.3°F cooler on this date compared to 20-30 years ago.
Planning for May 18th in Boulder, CO? Great weather for outdoor activities. Consider bringing rain gear or an umbrella.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 64° | 46° | 55° | — | — |
| 2024 | 73° | 54° | 63° | — | — |
| 2023 | 68° | 50° | 59° | — | — |
| 2022 | 82° | 55° | 69° | — | — |
| 2021 | 63° | 46° | 54° | — | — |
| 2020 | 82° | 50° | 66° | — | — |
| 2019 | 63° | 41° | 52° | — | — |
| 2018 | 64° | 46° | 55° | — | — |
| 2017 | 60° | 31° | 45° | 7.9" | 5.3" |
| 2016 | 65° | 40° | 52° | — | — |
| 2015 | 58° | 41° | 49° | 0.38" | — |
| 2014 | 82° | 40° | 61° | — | — |
| 2013 | 80° | 61° | 70° | — | — |
| 2012 | 80° | 47° | 63° | — | — |
| 2011 | 58° | 42° | 50° | 1.8" | — |
| 2010 | 74° | 51° | 62° | — | — |
| 2009 | 82° | 54° | 68° | — | — |
| 2008 | 82° | 47° | 64° | — | — |
| 2007 | 80° | 46° | 63° | — | — |
| 2006 | 85° | 52° | 68° | — | — |
| 2005 | 74° | 54° | 64° | — | — |
| 2004 | 72° | 52° | 62° | 0.08" | — |
| 2003 | 78° | 50° | 64° | 0.15" | — |
| 2002 | 72° | 41° | 56° | — | — |
| 2001 | 76° | 45° | 60° | 0.3" | — |
| 2000 | 51° | 39° | 45° | 0.23" | — |
| 1999 | 76° | 39° | 57° | — | — |
| 1998 | 83° | 54° | 68° | — | — |
| 1997 | 78° | 55° | 67° | — | — |
| 1996warmest | 90° | 51° | 70° | — | — |
| 1995 | 70° | 35° | 52° | 0.03" | — |
| 1994 | 85° | 50° | 67° | — | — |
| 1993 | 69° | 43° | 56° | 0.03" | — |
| 1992 | 87° | 48° | 68° | — | — |
| 1991 | 72° | 52° | 62° | 0.13" | — |
| 1990 | 76° | 41° | 58° | — | — |
| 1989 | 79° | 46° | 62° | — | — |
| 1988 | 71° | 53° | 62° | 0.89" | — |
| 1987 | 77° | 45° | 61° | 0.03" | — |
| 1986 | 71° | 39° | 55° | — | — |
| 1985 | 73° | 40° | 56° | — | — |
| 1984 | 77° | 42° | 60° | 0.23" | — |
| 1983 | 60° | 33° | 47° | 0.13" | — |
| 1982 | 76° | 42° | 59° | 0.15" | — |
| 1981 | 46° | 41° | 44° | 0.51" | — |
| 1980 | 63° | 36° | 49° | — | — |
| 1979 | 82° | 47° | 64° | — | — |
| 1978 | 70° | 35° | 52° | — | — |
| 1977 | 77° | 41° | 59° | — | — |
| 1976 | 83° | 46° | 64° | — | — |
| 1975 | 73° | 48° | 61° | — | — |
| 1974 | 76° | 51° | 63° | — | — |
| 1973 | 83° | 48° | 65° | — | — |
| 1972 | 79° | 52° | 65° | — | — |
| 1971coldest | 52° | 35° | 43° | 0.53" | — |
55 years of data from BOULDER MUNI AP