Weather on September 21
Saint Louis, MO
55 Years of Data
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.
| 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° | — | — | — | — |
Saint Louis, MO Temperature Range by Month
Average monthly highs and lows. The shaded band shows the typical daily temperature range.
Saint Louis, MO Monthly Precipitation
Average rainfall and snowfall per month, in inches.
Saint Louis, MO Daily Temperature Calendar
Average daily high temperature for every day of the year. Each cell is the climatological mean for that calendar day across 55 years of NOAA data.
Best Time to Visit Saint Louis, MO
Saint Louis, MO has no months that meet our "pleasant" threshold — every season has tradeoffs.