Weather on September 30
Longmont, CO
55 Years of Data
Avg High
75°F
Avg Low
42°F
Warmest
2024
71°F avg
Coldest
1985
30°F avg
About This Date
September 30th in Longmont, CO typically brings pleasant fall weather, with average highs around 75°F and lows near 42°F — a 33°F daily swing. Over 55 years of records, the warmest September 30th was in 2024 (71°F average), while the coldest was 1985 (30°F) — a 41°F range across recorded history. Rain or other precipitation has occurred on about 22% of September 30th dates historically, with the wettest September 30th recording 0.89" of rain. The last decade has been 2.6°F warmer on this date compared to 20-30 years ago.
The last decade has been 2.6°F warmer on this date compared to 20-30 years ago.
Planning for September 30th in Longmont, CO? Great weather for outdoor activities.
Warming Trend
2.1°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 75° | 55° | 65° | — | — |
| 2024warmest | 89° | 53° | 71° | — | — |
| 2023 | 79° | 46° | 62° | — | — |
| 2022 | 85° | 49° | 67° | — | — |
| 2021 | 70° | 44° | 57° | 0.43" | — |
| 2020 | 83° | 38° | 60° | — | — |
| 2019 | 85° | 48° | 66° | — | — |
| 2018 | 83° | 40° | 61° | — | — |
| 2017 | 62° | 43° | 52° | 0.05" | — |
| 2016 | 73° | 51° | 62° | 0.03" | — |
| 2015 | 77° | 52° | 64° | — | — |
| 2014 | 67° | 41° | 54° | 0.08" | — |
| 2013 | 81° | 53° | 67° | — | — |
| 2012 | 75° | 52° | 63° | — | — |
| 2011 | 80° | 39° | 60° | — | — |
| 2010 | 75° | 43° | 59° | — | — |
| 2009 | 82° | 50° | 66° | — | — |
| 2008 | 79° | 42° | 60° | — | — |
| 2007 | 74° | 46° | 60° | — | — |
| 2006 | 83° | 46° | 64° | — | — |
| 2005 | 84° | 48° | 66° | — | — |
| 2004 | 76° | 46° | 61° | 0.05" | — |
| 2003 | 69° | 39° | 54° | — | — |
| 2002 | 81° | 40° | 60° | — | — |
| 2001 | 85° | 46° | 65° | — | — |
| 2000 | 82° | 50° | 66° | 0.05" | — |
| 1999 | 69° | 21° | 45° | — | — |
| 1998 | 83° | 42° | 62° | 0.03" | — |
| 1997 | 81° | 36° | 58° | — | — |
| 1996 | 82° | 38° | 60° | — | — |
| 1995 | 67° | 44° | 55° | 0.43" | — |
| 1994 | 92° | 46° | 69° | — | — |
| 1993 | 77° | 35° | 56° | — | — |
| 1992 | 85° | 40° | 62° | — | — |
| 1991 | 83° | 51° | 67° | 0.89" | — |
| 1990 | 62° | 34° | 48° | 0.03" | — |
| 1989 | 81° | 42° | 61° | — | — |
| 1988 | 69° | 28° | 49° | — | — |
| 1987 | 62° | 36° | 49° | — | — |
| 1986 | 63° | 35° | 49° | — | — |
| 1985coldest | 43° | 18° | 30° | — | — |
| 1984 | 54° | 25° | 39° | — | — |
| 1983 | 70° | 52° | 61° | — | — |
| 1982 | 72° | 38° | 55° | — | — |
| 1981 | 86° | 49° | 67° | — | — |
| 1980 | 82° | 42° | 62° | — | — |
| 1979 | 84° | 44° | 64° | — | — |
| 1978 | 72° | 38° | 55° | — | — |
| 1977 | 84° | 49° | 66° | — | — |
| 1976 | 76° | 37° | 56° | — | — |
| 1975 | 77° | 39° | 58° | 0.74" | — |
| 1974 | 76° | 35° | 55° | — | — |
| 1973 | 59° | 34° | 46° | 0.03" | — |
| 1972 | 63° | 32° | 47° | — | — |
| 1971 | 61° | 38° | 49° | — | — |
55 years of data from LONGMONT 2 ESE