Weather on September 23
Longmont, CO
55 Years of Data
Avg High
73°F
Avg Low
42°F
Warmest
2014
69°F avg
Coldest
2000
37°F avg
About This Date
September 23rd in Longmont, CO typically brings pleasant fall weather, with average highs around 73°F and lows near 42°F — a 31°F daily swing. Over 55 years of records, the warmest September 23rd was in 2014 (69°F average), while the coldest was 2000 (37°F) — a 32°F range across recorded history. Rain or other precipitation has occurred on about 16% of September 23rd dates historically, with the wettest September 23rd recording 0.89" of rain. The last decade has been 5.8°F warmer on this date compared to 20-30 years ago.
The last decade has been 5.8°F warmer on this date compared to 20-30 years ago.
Planning for September 23rd in Longmont, CO? Great weather for outdoor activities.
Warming Trend
1.1°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 80° | 51° | 66° | 0.2" | — |
| 2024 | 63° | 43° | 53° | 0.61" | — |
| 2023 | 78° | 48° | 63° | — | — |
| 2022 | 57° | 47° | 52° | 0.05" | — |
| 2021 | 79° | 39° | 59° | — | — |
| 2020 | 86° | 50° | 68° | — | — |
| 2019 | 69° | 43° | 56° | — | — |
| 2018 | 87° | 47° | 67° | — | — |
| 2017 | 71° | 47° | 59° | 0.03" | — |
| 2016 | 79° | 49° | 64° | — | — |
| 2015 | 84° | 51° | 68° | — | — |
| 2014warmest | 81° | 57° | 69° | — | — |
| 2013 | 68° | 49° | 58° | 0.89" | — |
| 2012 | 88° | 47° | 67° | — | — |
| 2011 | 82° | 46° | 64° | — | — |
| 2010 | 79° | 49° | 64° | — | — |
| 2009 | 52° | 43° | 47° | 0.08" | — |
| 2008 | 77° | 43° | 60° | — | — |
| 2007 | 76° | 58° | 67° | — | — |
| 2006 | 58° | 35° | 46° | — | — |
| 2005 | 79° | 43° | 61° | — | — |
| 2004 | 60° | 36° | 48° | — | — |
| 2003 | 78° | 42° | 60° | — | — |
| 2002 | 71° | 38° | 54° | — | — |
| 2001 | 85° | 46° | 65° | — | — |
| 2000coldest | 45° | 29° | 37° | 0.33" | — |
| 1999 | 81° | 36° | 58° | — | — |
| 1998 | 68° | 42° | 55° | — | — |
| 1997 | 57° | 43° | 50° | 0.69" | — |
| 1996 | 82° | 40° | 61° | — | — |
| 1995 | 63° | 24° | 43° | — | — |
| 1994 | 67° | 32° | 49° | — | — |
| 1993 | 56° | 43° | 49° | 0.1" | — |
| 1992 | 84° | 44° | 64° | — | — |
| 1991 | 69° | 32° | 51° | — | — |
| 1990 | 69° | 41° | 55° | — | — |
| 1989 | 70° | 35° | 52° | — | — |
| 1988 | 72° | 30° | 51° | — | — |
| 1987 | 79° | 39° | 59° | — | — |
| 1986 | 69° | 54° | 61° | — | — |
| 1985 | 58° | 31° | 44° | — | — |
| 1984 | 76° | 39° | 57° | — | — |
| 1983 | 66° | 34° | 50° | — | — |
| 1982 | 88° | 48° | 68° | — | — |
| 1981 | 87° | 49° | 68° | — | — |
| 1980 | 66° | 38° | 52° | — | — |
| 1979 | 86° | 48° | 67° | — | — |
| 1978 | 80° | 37° | 59° | — | — |
| 1977 | 77° | 43° | 60° | — | — |
| 1976 | 75° | 44° | 60° | — | — |
| 1975 | 74° | 37° | 55° | — | — |
| 1974 | 74° | 39° | 56° | — | — |
| 1973 | 79° | 40° | 59° | — | — |
| 1972 | 81° | 41° | 61° | — | — |
| 1971 | 56° | 32° | 44° | — | — |
55 years of data from LONGMONT 2 ESE