Weather on September 3
Longmont, CO
55 Years of Data
Avg High
85°F
Avg Low
51°F
Warmest
2019
79°F avg
Coldest
1974
49°F avg
About This Date
September 3rd in Longmont, CO typically brings warm fall weather, with average highs around 85°F and lows near 51°F — a 34°F daily swing. Over 55 years of records, the warmest September 3rd was in 2019 (79°F average), while the coldest was 1974 (49°F) — a 30°F range across recorded history. Rain or other precipitation has occurred on about 24% of September 3rd dates historically, with the wettest September 3rd recording 3.1" of rain. The last decade has been 3.6°F warmer on this date compared to 20-30 years ago.
The last decade has been 3.6°F warmer on this date compared to 20-30 years ago.
Planning for September 3rd in Longmont, CO? Stay hydrated and seek shade during peak afternoon hours.
Warming Trend
1.4°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 86° | 52° | 69° | — | — |
| 2024 | 88° | 54° | 71° | — | — |
| 2023 | 89° | 62° | 76° | 0.03" | — |
| 2022 | 93° | 56° | 74° | 0.03" | — |
| 2021 | 81° | 61° | 71° | — | — |
| 2020 | 89° | 49° | 69° | — | — |
| 2019warmest | 99° | 59° | 79° | — | — |
| 2018 | 80° | 57° | 69° | — | — |
| 2017 | 88° | 55° | 71° | — | — |
| 2016 | 88° | 52° | 70° | 0.08" | — |
| 2015 | 85° | 62° | 73° | 0.08" | — |
| 2014 | 93° | 53° | 73° | — | — |
| 2013 | 94° | 60° | 77° | — | — |
| 2012 | 89° | 60° | 75° | — | — |
| 2011 | 77° | 52° | 64° | — | — |
| 2010 | 79° | 40° | 59° | — | — |
| 2009 | 86° | 54° | 70° | — | — |
| 2008 | 71° | 42° | 57° | — | — |
| 2007 | 91° | 57° | 74° | — | — |
| 2006 | 74° | 40° | 57° | — | — |
| 2005 | 91° | 55° | 73° | — | — |
| 2004 | 91° | 51° | 71° | — | — |
| 2003 | 85° | 57° | 71° | — | — |
| 2002 | 85° | 45° | 65° | — | — |
| 2001 | 94° | 46° | 70° | — | — |
| 2000 | 86° | 54° | 70° | — | — |
| 1999 | 80° | 49° | 64° | 3.1" | — |
| 1998 | 90° | 47° | 68° | — | — |
| 1997 | 68° | 55° | 62° | — | — |
| 1996 | 91° | 46° | 69° | — | — |
| 1995 | 92° | 59° | 75° | — | — |
| 1994 | 88° | 53° | 70° | 0.1" | — |
| 1993 | 67° | 35° | 51° | 0.25" | — |
| 1992 | 86° | 45° | 65° | — | — |
| 1991 | 87° | 50° | 69° | 0.41" | — |
| 1990 | 87° | 50° | 69° | 0.13" | — |
| 1989 | 91° | 48° | 70° | — | — |
| 1988 | 83° | 46° | 64° | — | — |
| 1987 | 87° | — | — | — | — |
| 1986 | 78° | 46° | 62° | — | — |
| 1985 | 83° | 55° | 69° | 0.03" | — |
| 1984 | 80° | 44° | 62° | — | — |
| 1983 | 98° | 58° | 78° | — | — |
| 1982 | 85° | 50° | 67° | — | — |
| 1981 | 95° | 54° | 74° | 0.3" | — |
| 1980 | 90° | 48° | 69° | — | — |
| 1979 | 92° | 50° | 71° | — | — |
| 1978 | 92° | 53° | 72° | — | — |
| 1977 | 87° | 59° | 73° | — | — |
| 1976 | 89° | 46° | 68° | — | — |
| 1975 | 85° | 49° | 67° | 0.08" | — |
| 1974coldest | 58° | 40° | 49° | 0.05" | — |
| 1973 | 68° | 36° | 52° | — | — |
| 1972 | 65° | 48° | 56° | — | — |
| 1971 | 91° | 53° | 72° | — | — |
55 years of data from LONGMONT 2 ESE