Weather on September 21
Joliet, IL
55 Years of Data
Avg High
76°F
Avg Low
53°F
Warmest
2018
81°F avg
Coldest
1982
49°F avg
About This Date
September 21st in Joliet, IL typically brings pleasant fall weather, with average highs around 76°F and lows near 53°F. Over 54 years of records, the warmest September 21st was in 2018 (81°F average), while the coldest was 1982 (49°F) — a 32°F range across recorded history. Rain or other precipitation has occurred on about 26% of September 21st dates historically, with the wettest September 21st recording 2.84" of rain. The last decade has been 9.4°F warmer on this date compared to 20-30 years ago.
The last decade has been 9.4°F warmer on this date compared to 20-30 years ago.
Planning for September 21st in Joliet, IL? Great weather for outdoor activities.
Warming Trend
2.3°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 82° | 64° | 73° | 0.18" | — |
| 2024 | 90° | 52° | 71° | — | — |
| 2023 | 79° | 54° | 66° | — | — |
| 2022 | 93° | 60° | 77° | — | — |
| 2021 | — | 66° | — | 1.14" | — |
| 2020 | 71° | 46° | 59° | — | — |
| 2019 | 83° | 67° | 75° | — | — |
| 2018warmest | 94° | 69° | 81° | — | — |
| 2017 | 90° | 64° | 77° | — | — |
| 2016 | 83° | 66° | 74° | — | — |
| 2015 | 72° | 50° | 61° | — | — |
| 2014 | 79° | 56° | 67° | 0.86" | — |
| 2013 | 75° | 53° | 64° | — | — |
| 2012 | 70° | 49° | 59° | — | — |
| 2011 | 75° | 50° | 63° | — | — |
| 2010 | 84° | 63° | 73° | — | — |
| 2009 | 72° | 54° | 63° | 2.84" | — |
| 2008 | 83° | 57° | 70° | — | — |
| 2007 | 84° | 63° | 73° | — | — |
| 2006 | 62° | 43° | 52° | — | — |
| 2005 | 82° | 59° | 71° | — | — |
| 2004 | 78° | 53° | 66° | — | — |
| 2003 | 73° | 45° | 59° | — | — |
| 2002 | 74° | 61° | 67° | 1.22" | — |
| 2001 | 70° | 53° | 61° | 0.03" | — |
| 2000 | 63° | 45° | 54° | 0.91" | — |
| 1999 | 66° | 49° | 57° | — | — |
| 1998 | 88° | 64° | 76° | — | — |
| 1997 | 69° | 50° | 60° | — | — |
| 1996 | 69° | 53° | 61° | — | — |
| 1995 | 72° | 50° | 61° | — | — |
| 1994 | 84° | 58° | 71° | — | — |
| 1993 | 68° | 53° | 61° | 0.03" | — |
| 1992 | 66° | 49° | 57° | 1.83" | — |
| 1991 | 69° | 42° | 56° | 0.81" | — |
| 1990 | 73° | 48° | 61° | — | — |
| 1989 | 78° | 55° | 67° | — | — |
| 1988 | 70° | 49° | 59° | — | — |
| 1987 | 71° | 47° | 59° | — | — |
| 1986 | 76° | 60° | 68° | — | — |
| 1985 | 88° | 62° | 75° | — | — |
| 1984 | 85° | 56° | 70° | — | — |
| 1983 | 72° | 37° | 54° | 1.14" | — |
| 1982coldest | 58° | 40° | 49° | — | — |
| 1981 | 73° | 51° | 62° | — | — |
| 1980 | 89° | 62° | 76° | 0.08" | — |
| 1979 | 78° | 45° | 61° | — | — |
| 1978 | 90° | 55° | 72° | 0.99" | — |
| 1977 | 63° | 43° | 53° | — | — |
| 1976 | 68° | 43° | 55° | 0.1" | — |
| 1975 | 59° | 48° | 54° | — | — |
| 1974 | 69° | 50° | 60° | — | — |
| 1973 | 73° | 42° | 58° | — | — |
| 1971 | 74° | 38° | 56° | — | — |
54 years of data from JOLIET