Weather on August 21
Joliet, IL
55 Years of Data
Avg High
82°F
Avg Low
62°F
Warmest
1980
81°F avg
Coldest
1985
62°F avg
About This Date
August 21st 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 21st was in 1980 (81°F average), while the coldest was 1985 (62°F) — a 19°F range across recorded history. Rain or other precipitation has occurred on about 30% of August 21st dates historically, with the wettest August 21st recording 2.84" of rain. The last decade has been 1.2°F warmer on this date compared to 20-30 years ago.
The last decade has been 1.2°F warmer on this date compared to 20-30 years ago.
Planning for August 21st in Joliet, IL? Stay hydrated and seek shade during peak afternoon hours. Consider bringing rain gear or an umbrella.
Cooling Trend
0.4°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 79° | 65° | 72° | — | — |
| 2024 | 78° | 53° | 66° | — | — |
| 2023 | 91° | 70° | 80° | — | — |
| 2022 | 72° | 62° | 67° | 0.99" | — |
| 2021 | 87° | 70° | 78° | — | — |
| 2020 | 82° | 56° | 69° | — | — |
| 2019 | 76° | 60° | 68° | 0.43" | — |
| 2018 | 80° | 68° | 74° | 2.16" | — |
| 2017 | 85° | 62° | 73° | 1.78" | — |
| 2016 | 78° | 58° | 68° | 1.02" | — |
| 2015 | 74° | 56° | 65° | — | — |
| 2014 | 85° | 64° | 74° | 0.15" | — |
| 2013 | 85° | 63° | 74° | — | — |
| 2012 | 78° | 56° | 67° | — | — |
| 2011 | 78° | 67° | 72° | 2.84" | — |
| 2010 | 91° | 72° | 81° | 0.2" | — |
| 2009 | 77° | 57° | 67° | 0.25" | — |
| 2008 | 82° | 64° | 73° | — | — |
| 2007 | 76° | 69° | 72° | 2.26" | — |
| 2006 | 79° | 59° | 69° | — | — |
| 2005 | 84° | 64° | 74° | — | — |
| 2004 | 72° | 55° | 63° | 0.48" | — |
| 2003 | 88° | 64° | 76° | — | — |
| 2002 | 80° | 58° | 69° | — | — |
| 2001 | 80° | 57° | 69° | — | — |
| 2000 | 74° | 56° | 65° | — | — |
| 1999 | 80° | 56° | 68° | — | — |
| 1998 | 86° | 64° | 75° | — | — |
| 1997 | 73° | 58° | 65° | — | — |
| 1996 | 86° | 71° | 79° | — | — |
| 1995 | 86° | 65° | 75° | — | — |
| 1994 | 77° | 63° | 70° | 0.03" | — |
| 1993 | 82° | 64° | 73° | — | — |
| 1992 | 77° | 53° | 65° | — | — |
| 1991 | 84° | 58° | 71° | — | — |
| 1990 | 73° | 68° | 71° | 1.17" | — |
| 1989 | 84° | 62° | 73° | — | — |
| 1988 | 83° | 65° | 74° | — | — |
| 1986 | 90° | 54° | 72° | — | — |
| 1985coldest | 72° | 52° | 62° | — | — |
| 1984 | 81° | 56° | 68° | — | — |
| 1983 | 92° | 67° | 79° | — | — |
| 1982 | 85° | 58° | 71° | — | — |
| 1981 | 79° | 60° | 69° | — | — |
| 1980warmest | 94° | 68° | 81° | 0.25" | — |
| 1979 | 80° | 65° | 72° | 0.03" | — |
| 1978 | 82° | 54° | 68° | — | — |
| 1977 | 73° | 55° | 64° | 0.2" | — |
| 1976 | 85° | 62° | 73° | — | — |
| 1974 | 93° | 67° | 80° | — | — |
| 1973 | 84° | 56° | 70° | — | — |
| 1972 | 90° | 71° | 80° | — | — |
| 1971 | 93° | 63° | 78° | — | — |
53 years of data from JOLIET