Weather on March 18
Boulder, CO
55 Years of Data
Avg High
56°F
Avg Low
31°F
Warmest
2026
71°F avg
Coldest
2016
26°F avg
About This Date
March 18th in Boulder, CO typically brings cool spring weather, with average highs around 56°F and lows near 31°F — a 25°F daily swing. Over 56 years of records, the warmest March 18th was in 2026 (71°F average), while the coldest was 2016 (26°F) — a 45°F range across recorded history. Precipitation has occurred on 23% of recorded March 18th dates, with snow falling 16% of the time (heaviest snowfall: 16.9"). The last decade has been 5.6°F warmer on this date compared to 20-30 years ago.
The last decade has been 5.6°F warmer on this date compared to 20-30 years ago.
Planning for March 18th in Boulder, CO? Bring layers as temperatures can vary throughout the day.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2026warmest | 82° | 59° | 71° | — | — |
| 2025 | 63° | 32° | 47° | — | — |
| 2024 | 55° | 30° | 43° | — | — |
| 2023 | 46° | 19° | 33° | — | — |
| 2022 | 54° | 27° | 41° | — | — |
| 2021 | 43° | 23° | 33° | — | — |
| 2020 | 61° | 34° | 47° | — | — |
| 2019 | 45° | 30° | 38° | — | — |
| 2018 | 54° | 30° | 42° | — | — |
| 2017 | 80° | 36° | 58° | — | — |
| 2016coldest | 30° | 21° | 26° | 2.16" | 10.5" |
| 2015 | 64° | 36° | 50° | — | — |
| 2014 | 57° | 30° | 44° | — | — |
| 2013 | 48° | 31° | 39° | — | — |
| 2012 | 70° | 39° | 54° | — | — |
| 2011 | 56° | 31° | 43° | 0.1" | 0.1" |
| 2010 | 65° | 35° | 50° | — | — |
| 2009 | 68° | 38° | 53° | — | — |
| 2008 | 49° | 22° | 35° | — | — |
| 2007 | 76° | 45° | 60° | — | — |
| 2006 | 49° | 21° | 35° | — | — |
| 2005 | 49° | 29° | 39° | — | — |
| 2004 | 67° | 34° | 50° | — | — |
| 2003 | 41° | 32° | 37° | 6.27" | 11.7" |
| 2002 | 41° | 18° | 29° | — | — |
| 2001 | 46° | 22° | 34° | 0.05" | 0.1" |
| 2000 | 44° | 29° | 36° | — | — |
| 1999 | 56° | 24° | 40° | — | — |
| 1998 | 45° | 30° | 37° | 5.13" | 16.9" |
| 1997 | 61° | 29° | 45° | — | — |
| 1996 | 40° | 25° | 32° | 0.03" | — |
| 1995 | 69° | 35° | 52° | — | — |
| 1994 | 68° | 34° | 51° | — | — |
| 1993 | 61° | 29° | 45° | — | — |
| 1992 | 47° | 33° | 40° | 0.3" | 0.3" |
| 1991 | 64° | 36° | 50° | — | — |
| 1990 | 51° | 25° | 38° | — | — |
| 1989 | 62° | 26° | 44° | — | — |
| 1988 | 49° | 12° | 30° | — | — |
| 1987 | 60° | 28° | 44° | — | — |
| 1986 | 40° | 33° | 36° | — | — |
| 1985 | 64° | 38° | 51° | — | — |
| 1984 | 49° | 29° | 39° | 0.56" | 3" |
| 1983 | 32° | 22° | 27° | 0.1" | — |
| 1982 | 56° | 33° | 44° | — | — |
| 1981 | 48° | 26° | 37° | 0.74" | 3" |
| 1980 | 66° | 32° | 49° | — | — |
| 1979 | 53° | 33° | 43° | 1.7" | 1.5" |
| 1978 | 74° | 44° | 59° | — | — |
| 1977 | 45° | 30° | 37° | 0.03" | — |
| 1976 | 68° | 43° | 55° | — | — |
| 1975 | 59° | 34° | 46° | — | — |
| 1974 | 73° | 36° | 54° | 0.05" | — |
| 1973 | 63° | 36° | 49° | — | — |
| 1972 | 72° | 35° | 53° | — | — |
| 1971 | 37° | 21° | 29° | — | — |
56 years of data from BOULDER MUNI AP