Weather on September 20
Naperville, IL
55 Years of Data
Avg High
77°F
Avg Low
52°F
Warmest
1978
80°F avg
Coldest
1991
45°F avg
About This Date
September 20th in Naperville, IL typically brings pleasant fall weather, with average highs around 77°F and lows near 52°F — a 25°F daily swing. Over 55 years of records, the warmest September 20th was in 1978 (80°F average), while the coldest was 1991 (45°F) — a 35°F range across recorded history. Rain or other precipitation has occurred on about 29% of September 20th dates historically, with the wettest September 20th recording 2.16" of rain. The last decade has been 1.5°F warmer on this date compared to 20-30 years ago.
The last decade has been 1.5°F warmer on this date compared to 20-30 years ago.
Planning for September 20th in Naperville, IL? Great weather for outdoor activities.
Warming Trend
0.5°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 86° | 59° | 73° | 0.15" | — |
| 2024 | 88° | 53° | 70° | 0.18" | — |
| 2023 | 63° | 55° | 59° | 0.53" | — |
| 2022 | 79° | 57° | 68° | — | — |
| 2021 | 91° | 61° | 76° | — | — |
| 2020 | 66° | 37° | 52° | — | — |
| 2019 | 83° | 58° | 70° | 0.03" | — |
| 2018 | 80° | 64° | 72° | — | — |
| 2017 | 82° | 58° | 70° | — | — |
| 2016 | 88° | 57° | 72° | — | — |
| 2015 | 70° | 45° | 57° | — | — |
| 2014 | 75° | 47° | 61° | — | — |
| 2013 | 90° | 67° | 78° | 0.33" | — |
| 2012 | 73° | 38° | 55° | — | — |
| 2011 | 69° | 47° | 58° | — | — |
| 2010 | 69° | 55° | 62° | — | — |
| 2009 | 74° | 50° | 62° | 2.16" | — |
| 2008 | 78° | 53° | 66° | — | — |
| 2007 | 85° | 55° | 70° | — | — |
| 2006 | 62° | 40° | 51° | — | — |
| 2005 | 82° | 55° | 69° | 0.43" | — |
| 2004 | 78° | 47° | 62° | — | — |
| 2003 | 72° | 39° | 55° | — | — |
| 2002 | 80° | 69° | 75° | 0.3" | — |
| 2001 | 77° | 53° | 65° | 0.15" | — |
| 2000 | 90° | 53° | 71° | — | — |
| 1999 | 80° | 51° | 66° | 0.18" | — |
| 1998 | 88° | 62° | 75° | — | — |
| 1997 | 77° | 58° | 67° | 1.14" | — |
| 1996 | 75° | 48° | 62° | — | — |
| 1995 | 69° | 55° | 62° | 0.08" | — |
| 1994 | 86° | 54° | 70° | — | — |
| 1993 | 65° | 48° | 56° | — | — |
| 1992 | 69° | 44° | 57° | — | — |
| 1991coldest | 58° | 33° | 45° | — | — |
| 1990 | 72° | 44° | 58° | — | — |
| 1989 | 80° | 50° | 65° | — | — |
| 1988 | 72° | 55° | 63° | — | — |
| 1987 | 63° | 52° | 57° | 0.05" | — |
| 1986 | 72° | 64° | 68° | — | — |
| 1985 | 87° | 64° | 76° | — | — |
| 1984 | 84° | 57° | 71° | — | — |
| 1983 | 86° | 47° | 66° | — | — |
| 1982 | 70° | 44° | 57° | — | — |
| 1981 | 77° | 48° | 63° | — | — |
| 1980 | 88° | 64° | 76° | 0.18" | — |
| 1979 | 77° | 42° | 60° | — | — |
| 1978warmest | 90° | 71° | 80° | — | — |
| 1977 | 66° | 48° | 57° | — | — |
| 1976 | 83° | 53° | 68° | 0.15" | — |
| 1975 | 70° | 44° | 57° | — | — |
| 1974 | 81° | 54° | 67° | 0.1" | — |
| 1973 | 68° | 48° | 58° | — | — |
| 1972 | 83° | 60° | 71° | — | — |
| 1971 | 66° | 46° | 56° | — | — |
55 years of data from WHEATON 3 SE