Weather on August 15
Joliet, IL
55 Years of Data
Avg High
82°F
Avg Low
61°F
Warmest
1988
85°F avg
Coldest
1979
61°F avg
About This Date
August 15th in Joliet, IL typically brings warm summer weather, with average highs around 82°F and lows near 61°F. Over 53 years of records, the warmest August 15th was in 1988 (85°F average), while the coldest was 1979 (61°F) — a 24°F range across recorded history. Rain or other precipitation has occurred on about 17% of August 15th dates historically, with the wettest August 15th recording 4.06" of rain. The last decade has been 1.3°F warmer on this date compared to 20-30 years ago.
The last decade has been 1.3°F warmer on this date compared to 20-30 years ago.
Planning for August 15th in Joliet, IL? Stay hydrated and seek shade during peak afternoon hours.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 91° | 67° | 79° | — | — |
| 2024 | 83° | 59° | 71° | 0.38" | — |
| 2023 | 73° | 52° | 62° | 4.06" | — |
| 2022 | 74° | 66° | 70° | — | — |
| 2021 | 81° | 57° | 69° | — | — |
| 2020 | 87° | 66° | 77° | — | — |
| 2019 | 85° | 62° | 73° | — | — |
| 2018 | 88° | 64° | 76° | — | — |
| 2017 | 81° | 60° | 70° | — | — |
| 2016 | 76° | 68° | 72° | 0.76" | — |
| 2015 | 86° | 65° | 75° | 1.4" | — |
| 2014 | 74° | 52° | 63° | — | — |
| 2013 | 74° | 54° | 64° | — | — |
| 2012 | 82° | 58° | 70° | — | — |
| 2011 | 77° | 58° | 67° | — | — |
| 2010 | 86° | 72° | 79° | — | — |
| 2009 | 84° | 64° | 74° | — | — |
| 2008 | 79° | 62° | 70° | — | — |
| 2007 | 84° | 66° | 75° | 0.76" | — |
| 2006 | 80° | 59° | 70° | — | — |
| 2005 | 76° | 61° | 68° | — | — |
| 2004 | 73° | 50° | 62° | — | — |
| 2003 | 87° | 68° | 78° | — | — |
| 2002 | 80° | 65° | 72° | — | — |
| 2001 | 80° | 59° | 70° | — | — |
| 2000 | 86° | 66° | 76° | — | — |
| 1999 | 76° | 56° | 66° | — | — |
| 1998 | 83° | 64° | 73° | — | — |
| 1997 | 76° | 59° | 67° | — | — |
| 1996 | 86° | 62° | 74° | — | — |
| 1995 | 94° | 75° | 84° | — | — |
| 1994 | 71° | 53° | 62° | — | — |
| 1993 | 87° | 68° | 78° | — | — |
| 1992 | 70° | 57° | 63° | — | — |
| 1991 | 90° | 56° | 73° | — | — |
| 1990 | 78° | 54° | 66° | — | — |
| 1989 | 79° | 63° | 71° | 1.32" | — |
| 1988warmest | 93° | 77° | 85° | — | — |
| 1986 | 86° | 56° | 71° | — | — |
| 1985 | 80° | 60° | 70° | 2.24" | — |
| 1984 | 88° | 53° | 70° | — | — |
| 1983 | 86° | 60° | 73° | — | — |
| 1982 | 82° | 55° | 69° | — | — |
| 1981 | 75° | 64° | 70° | 2.16" | — |
| 1980 | 80° | 66° | 73° | 0.2" | — |
| 1979coldest | 73° | 49° | 61° | — | — |
| 1978 | 86° | 65° | 75° | — | — |
| 1977 | 81° | 57° | 69° | — | — |
| 1976 | 79° | 58° | 68° | — | — |
| 1974 | 91° | 65° | 78° | — | — |
| 1973 | 85° | 59° | 72° | — | — |
| 1972 | 90° | 66° | 78° | — | — |
| 1971 | 80° | 60° | 70° | — | — |
53 years of data from JOLIET