Weather on August 20
Joliet, IL
55 Years of Data
Avg High
82°F
Avg Low
62°F
Warmest
1983
84°F avg
Coldest
1977
62°F avg
About This Date
August 20th in Joliet, IL typically brings warm summer weather, with average highs around 82°F and lows near 62°F. Over 53 years of records, the warmest August 20th was in 1983 (84°F average), while the coldest was 1977 (62°F) — a 22°F range across recorded history. Rain or other precipitation has occurred on about 28% of August 20th dates historically, with the wettest August 20th recording 3.63" 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 August 20th in Joliet, IL? Stay hydrated and seek shade during peak afternoon hours.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 79° | 67° | 73° | — | — |
| 2024 | 78° | 58° | 68° | — | — |
| 2023 | 82° | 59° | 71° | — | — |
| 2022 | 82° | 61° | 71° | 1.93" | — |
| 2021 | 88° | 70° | 79° | — | — |
| 2020 | 81° | 56° | 68° | — | — |
| 2019 | 85° | 69° | 77° | — | — |
| 2018 | 85° | 65° | 75° | — | — |
| 2017 | 81° | 62° | 71° | — | — |
| 2016 | 87° | 69° | 78° | 0.25" | — |
| 2015 | 75° | 58° | 66° | — | — |
| 2014 | 83° | 64° | 73° | 0.05" | — |
| 2013 | 84° | 59° | 72° | — | — |
| 2012 | 78° | 57° | 68° | — | — |
| 2011 | 87° | 67° | 77° | — | — |
| 2010 | 88° | 65° | 76° | — | — |
| 2009 | 79° | 63° | 71° | 1.47" | — |
| 2008 | 85° | 63° | 74° | — | — |
| 2007 | 69° | 65° | 67° | 2.67" | — |
| 2006 | 79° | 63° | 71° | — | — |
| 2005 | 86° | 71° | 79° | 0.48" | — |
| 2004 | 71° | 58° | 64° | — | — |
| 2003 | 82° | 62° | 72° | — | — |
| 2002 | 80° | 58° | 69° | 0.2" | — |
| 2001 | 74° | 58° | 66° | — | — |
| 2000 | 74° | 59° | 66° | — | — |
| 1999 | 76° | 61° | 68° | 0.25" | — |
| 1998 | 80° | 61° | 70° | — | — |
| 1997 | 71° | 57° | 64° | 0.08" | — |
| 1996 | 85° | 69° | 77° | — | — |
| 1995 | 90° | 73° | 81° | — | — |
| 1994 | 89° | 68° | 79° | — | — |
| 1993 | 84° | 69° | 77° | 0.84" | — |
| 1992 | 77° | 53° | 65° | — | — |
| 1991 | 78° | 56° | 67° | — | — |
| 1990 | 87° | 70° | 78° | 3.63" | — |
| 1989 | 79° | 58° | 68° | 0.36" | — |
| 1988 | 75° | 69° | 72° | — | — |
| 1986 | 87° | 56° | 71° | — | — |
| 1985 | 77° | 53° | 65° | — | — |
| 1984 | 80° | 57° | 69° | — | — |
| 1983warmest | 97° | 71° | 84° | — | — |
| 1982 | 84° | 59° | 72° | — | — |
| 1981 | 77° | 58° | 67° | — | — |
| 1980 | 86° | 66° | 76° | 1.73" | — |
| 1979 | 81° | 65° | 73° | 2.36" | — |
| 1978 | 79° | 54° | 66° | — | — |
| 1977coldest | 71° | 53° | 62° | 0.99" | — |
| 1976 | 85° | 60° | 72° | — | — |
| 1974 | 92° | 68° | 80° | — | — |
| 1973 | 87° | 66° | 77° | — | — |
| 1972 | 88° | 67° | 77° | — | — |
| 1971 | 94° | 68° | 81° | — | — |
53 years of data from JOLIET