Weather on September 21
Saint Louis, MO
55 Years of Data
Avg High
79°F
Avg Low
58°F
Warmest
2017
86°F avg
Coldest
1995
54°F avg
About This Date
September 21st in Saint Louis, MO typically brings pleasant fall weather, with average highs around 79°F and lows near 58°F. Over 53 years of records, the warmest September 21st was in 2017 (86°F average), while the coldest was 1995 (54°F) — a 32°F range across recorded history. Rain or other precipitation has occurred on about 34% of September 21st dates historically, with the wettest September 21st recording 4.06" of rain. The last decade has been 9.1°F warmer on this date compared to 20-30 years ago.
The last decade has been 9.1°F warmer on this date compared to 20-30 years ago.
Planning for September 21st in Saint Louis, MO? Great weather for outdoor activities. Consider bringing rain gear or an umbrella.
Warming Trend
1.3°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 87° | 60° | 74° | 0.41" | — |
| 2024 | 94° | 68° | 81° | — | — |
| 2023 | 85° | 59° | 72° | — | — |
| 2022 | 97° | 67° | 82° | 4.06" | — |
| 2021 | 74° | 56° | 65° | 2.51" | — |
| 2020 | 79° | 44° | 61° | — | — |
| 2019 | 84° | 70° | 77° | — | — |
| 2018 | 83° | 65° | 74° | 0.36" | — |
| 2017warmest | 94° | 78° | 86° | — | — |
| 2016 | 91° | 70° | 80° | — | — |
| 2015 | 74° | 54° | 64° | — | — |
| 2014 | 80° | 58° | 69° | 0.03" | — |
| 2013 | 71° | 54° | 62° | 0.08" | — |
| 2012 | 79° | 56° | 67° | — | — |
| 2011 | 76° | 56° | 66° | — | — |
| 2010 | 90° | 64° | 77° | — | — |
| 2009 | 69° | 61° | 65° | 0.51" | — |
| 2008 | 73° | 61° | 67° | — | — |
| 2007 | 90° | 60° | 75° | — | — |
| 2006 | 67° | 47° | 57° | — | — |
| 2005 | 82° | 59° | 71° | — | — |
| 2004 | 82° | 47° | 64° | — | — |
| 2003 | 76° | 55° | 65° | — | — |
| 2002 | 70° | 56° | 63° | 0.38" | — |
| 2001 | 81° | 57° | 69° | 0.58" | — |
| 2000 | 76° | 46° | 61° | 0.18" | — |
| 1999 | 69° | 48° | 59° | 0.03" | — |
| 1998 | 89° | 69° | 79° | — | — |
| 1997 | 67° | 56° | 61° | — | — |
| 1996 | 78° | 59° | 69° | — | — |
| 1995coldest | 61° | 48° | 54° | 0.1" | — |
| 1994 | 83° | 52° | 67° | — | — |
| 1993 | 79° | 57° | 68° | — | — |
| 1992 | 78° | 70° | 74° | 0.58" | — |
| 1991 | 68° | 59° | 64° | — | — |
| 1990 | 75° | 51° | 63° | 1.27" | — |
| 1989 | 78° | 56° | 67° | — | — |
| 1988 | 86° | 67° | 76° | — | — |
| 1987 | 74° | 44° | 59° | — | — |
| 1986 | 91° | 65° | 78° | — | — |
| 1985 | 84° | 57° | 71° | — | — |
| 1982 | 67° | 47° | 57° | — | — |
| 1981 | 83° | 59° | 71° | — | — |
| 1980 | 90° | 64° | 77° | — | — |
| 1979 | — | 52° | — | — | — |
| 1978 | 93° | 59° | 76° | 1.42" | — |
| 1977 | 72° | 50° | 61° | — | — |
| 1976 | 69° | 47° | 58° | 0.03" | — |
| 1975 | 68° | 46° | 57° | — | — |
| 1974 | 75° | 55° | 65° | — | — |
| 1973 | 67° | 61° | 64° | 0.05" | — |
| 1972 | 93° | 67° | 80° | 0.53" | — |
| 1971 | 60° | — | — | — | — |
53 years of data from ST LOUIS ST LOUIS UNIV