Weather on May 15
Joliet, IL
55 Years of Data
Avg High
70°F
Avg Low
48°F
Warmest
2025
80°F avg
Coldest
2016
42°F avg
About This Date
May 15th in Joliet, IL typically brings pleasant spring weather, with average highs around 70°F and lows near 48°F. Over 53 years of records, the warmest May 15th was in 2025 (80°F average), while the coldest was 2016 (42°F) — a 38°F range across recorded history. Rain or other precipitation has occurred on about 42% of May 15th dates historically, with the wettest May 15th recording 3.28" of rain. The last decade has been 5.7°F warmer on this date compared to 20-30 years ago.
The last decade has been 5.7°F warmer on this date compared to 20-30 years ago.
Planning for May 15th in Joliet, IL? Great weather for outdoor activities. Consider bringing rain gear or an umbrella.
Warming Trend
0.7°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025warmest | 93° | 67° | 80° | — | — |
| 2024 | 67° | 53° | 60° | — | — |
| 2023 | 63° | 52° | 57° | 0.43" | — |
| 2022 | 88° | 61° | 74° | — | — |
| 2021 | 70° | 41° | 55° | — | — |
| 2020 | 72° | 41° | 56° | 3.28" | — |
| 2019 | 70° | 40° | 55° | — | — |
| 2018 | 86° | 57° | 72° | 0.76" | — |
| 2017 | 82° | 52° | 67° | — | — |
| 2016coldest | 49° | 36° | 42° | — | — |
| 2015 | 66° | 47° | 56° | 0.08" | — |
| 2014 | 56° | 43° | 49° | 0.76" | — |
| 2013 | 91° | 57° | 74° | — | — |
| 2012 | 80° | 46° | 63° | — | — |
| 2011 | 54° | 47° | 50° | 0.89" | — |
| 2010 | 66° | 47° | 56° | — | — |
| 2009 | 70° | 53° | 61° | — | — |
| 2008 | 64° | 44° | 54° | — | — |
| 2007 | 88° | 58° | 73° | — | — |
| 2006 | 56° | 43° | 49° | 0.36" | — |
| 2005 | 66° | 44° | 55° | — | — |
| 2004 | 67° | 50° | 58° | 1.75" | — |
| 2003 | 73° | 48° | 61° | 0.2" | — |
| 2002 | 56° | 44° | 50° | — | — |
| 2001 | 67° | 49° | 58° | 0.43" | — |
| 2000 | 65° | 41° | 53° | — | — |
| 1999 | 69° | 47° | 58° | — | — |
| 1998 | 88° | 58° | 73° | — | — |
| 1997 | 60° | 37° | 49° | 0.1" | — |
| 1996 | 55° | 38° | 46° | 0.18" | — |
| 1995 | 69° | 46° | 58° | — | — |
| 1994 | 67° | 53° | 60° | 0.25" | — |
| 1993 | 80° | 48° | 64° | — | — |
| 1992 | 61° | 46° | 53° | 0.05" | — |
| 1991 | 83° | 62° | 72° | — | — |
| 1990 | 66° | 48° | 57° | — | — |
| 1989 | 65° | 46° | 55° | — | — |
| 1988 | 83° | 46° | 64° | — | — |
| 1987 | 88° | 53° | 70° | — | — |
| 1986 | 70° | 53° | 61° | — | — |
| 1985 | 86° | 57° | 72° | 0.69" | — |
| 1984 | 69° | 39° | 54° | — | — |
| 1983 | 66° | 46° | 56° | 0.53" | — |
| 1981 | 50° | 45° | 47° | 2.34" | — |
| 1980 | 67° | 42° | 54° | 0.05" | — |
| 1979 | 62° | 42° | 52° | 1.35" | — |
| 1978 | 49° | 41° | 45° | 0.05" | — |
| 1977 | 86° | 55° | 71° | — | — |
| 1976 | 72° | 54° | 63° | — | — |
| 1974 | 65° | 42° | 53° | — | — |
| 1973 | 65° | 38° | 51° | 0.15" | — |
| 1972 | 66° | 50° | 58° | 0.05" | — |
| 1971 | 80° | 52° | 66° | — | — |
53 years of data from JOLIET