Weather on September 15
Joliet, IL
55 Years of Data
Avg High
77°F
Avg Low
54°F
Warmest
1994
81°F avg
Coldest
2011
51°F avg
About This Date
September 15th in Joliet, IL typically brings pleasant fall weather, with average highs around 77°F and lows near 54°F. Over 54 years of records, the warmest September 15th was in 1994 (81°F average), while the coldest was 2011 (51°F) — a 30°F range across recorded history. Rain or other precipitation has occurred on about 30% of September 15th dates historically, with the wettest September 15th recording 4.9" 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 15th in Joliet, IL? Great weather for outdoor activities. Consider bringing rain gear or an umbrella.
Warming Trend
0.8°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 88° | 64° | 76° | — | — |
| 2024 | 88° | 66° | 77° | — | — |
| 2023 | 72° | 50° | 61° | — | — |
| 2022 | 79° | 56° | 67° | — | — |
| 2021 | 86° | 59° | 73° | — | — |
| 2020 | 74° | 56° | 65° | — | — |
| 2019 | 80° | 56° | 68° | 4.06" | — |
| 2018 | 86° | 62° | 74° | — | — |
| 2017 | 78° | 60° | 69° | — | — |
| 2016 | 75° | 62° | 69° | — | — |
| 2015 | 81° | 53° | 67° | — | — |
| 2014 | 66° | 41° | 54° | — | — |
| 2013 | 70° | 48° | 59° | — | — |
| 2012 | 74° | 51° | 62° | — | — |
| 2011coldest | 61° | 42° | 51° | 0.08" | — |
| 2010 | 79° | 56° | 67° | — | — |
| 2009 | 82° | 56° | 69° | — | — |
| 2008 | 68° | 57° | 63° | 4.9" | — |
| 2007 | 78° | 50° | 64° | — | — |
| 2006 | 75° | 56° | 65° | — | — |
| 2005 | 78° | 58° | 68° | — | — |
| 2004 | 86° | 65° | 75° | — | — |
| 2003 | 85° | 55° | 70° | 0.23" | — |
| 2002 | 86° | 59° | 73° | — | — |
| 2001 | 65° | 50° | 57° | — | — |
| 2000 | 81° | 51° | 66° | 0.03" | — |
| 1999 | 72° | 47° | 59° | — | — |
| 1998 | 78° | 70° | 74° | 0.56" | — |
| 1997 | 80° | 54° | 67° | — | — |
| 1996 | 63° | 46° | 54° | — | — |
| 1995 | 79° | 55° | 67° | — | — |
| 1994warmest | 91° | 71° | 81° | — | — |
| 1993 | 71° | 51° | 61° | 3.81" | — |
| 1992 | 81° | 60° | 70° | 0.69" | — |
| 1991 | 89° | 69° | 79° | — | — |
| 1990 | 84° | 53° | 69° | 0.76" | — |
| 1989 | 63° | 50° | 56° | — | — |
| 1988 | 81° | 52° | 66° | — | — |
| 1987 | 80° | 54° | 67° | 0.03" | — |
| 1986 | 78° | 45° | 61° | — | — |
| 1985 | 68° | 46° | 57° | — | — |
| 1984 | 67° | 46° | 56° | 0.1" | — |
| 1983 | 72° | 48° | 60° | — | — |
| 1982 | 84° | 60° | 72° | 0.05" | — |
| 1981 | 82° | 54° | 68° | — | — |
| 1980 | 70° | 54° | 62° | 0.05" | — |
| 1979 | 67° | 45° | 56° | — | — |
| 1978 | 81° | 53° | 67° | 0.28" | — |
| 1977 | 72° | 51° | 61° | 1.91" | — |
| 1976 | 85° | 63° | 74° | 0.05" | — |
| 1975 | 70° | 51° | 60° | — | — |
| 1974 | 76° | 52° | 64° | — | — |
| 1973 | 78° | 47° | 62° | — | — |
| 1971 | 90° | 51° | 70° | — | — |
54 years of data from JOLIET