September weather in Joliet, IL
The average temperature in Joliet in September is 65.7°F (55.3°F–76.2°F). Average precipitation: 3.17 inches.
September is a fall month in Joliet, and is warmer than the annual average of 50.4°F. Daily temperatures swing about 20.9°F between overnight low and afternoon high. Expect about 8 days with precipitation. Daylight averages about 12h 16m. For travel, September is one of the best months of the year to visit.
Avg High
76.2°F
Avg Low
55.3°F
Precipitation
3.17 in
Daylight
12h 16m
September records in Joliet
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 91.9°F (2000) | 46.9°F (2009) | 3.67 in (1977) |
| September 2 | 95.0°F (1984) | 46.0°F (2017) | 1.23 in (1952) |
| September 3 | 93.0°F (2000) | 46.0°F (2009) | 1.50 in (2010) |
| September 4 | 91.0°F (1999) | 46.0°F (2009) | 1.24 in (2018) |
| September 5 | 93.0°F (1999) | 46.9°F (1982) | 2.18 in (2008) |
| September 6 | 91.9°F (1983) | 45.0°F (1988) | 2.90 in (2023) |
| September 7 | 95.0°F (1990) | 39.9°F (1986) | 1.34 in (1989) |
| September 8 | 93.0°F (1978) | 37.9°F (1986) | 1.45 in (1946) |
| September 9 | 97.0°F (1978) | 37.0°F (1986) | 1.72 in (1965) |
| September 10 | 95.0°F (1978) | 44.1°F (1976) | 2.00 in (1992) |
| September 11 | 95.0°F (1978) | 45.0°F (1993) | 0.55 in (2014) |
| September 12 | 93.9°F (2000) | 45.0°F (1993) | 1.92 in (1974) |
| September 13 | 95.0°F (1991) | 39.0°F (2014) | 2.32 in (1961) |
| September 14 | 93.9°F (1991) | 37.9°F (2014) | 2.60 in (2008) |
| September 15 | 91.0°F (1994) | 41.0°F (2014) | 2.52 in (1970) |
| September 16 | 90.0°F (1994) | 41.0°F (1984) | 0.90 in (2004) |
| September 17 | 88.0°F (2018) | 41.0°F (1984) | 2.25 in (1980) |
| September 18 | 91.9°F (1988) | 37.9°F (1991) | 2.45 in (1977) |
| September 19 | 89.1°F (2000) | 39.0°F (1991) | 2.30 in (2015) |
| September 20 | 91.9°F (1978) | 39.0°F (1991) | 1.91 in (1986) |
| September 21 | 93.9°F (2018) | 37.0°F (1983) | 1.40 in (1950) |
| September 22 | 91.0°F (2017) | 33.1°F (1983) | 2.77 in (1951) |
| September 23 | 93.0°F (2017) | 32.0°F (1983) | 1.32 in (1961) |
| September 24 | 93.0°F (2017) | 32.0°F (1983) | 2.94 in (1961) |
| September 25 | 89.1°F (2010) | 35.1°F (1983) | 1.63 in (1973) |
| September 26 | 90.0°F (1986) | 35.1°F (1983) | 1.20 in (1951) |
| September 27 | 91.0°F (1998) | 36.0°F (1991) | 1.50 in (1996) |
| September 28 | 88.0°F (2021) | 39.9°F (1981) | 4.10 in (2019) |
| September 29 | 84.9°F (1986) | 36.0°F (1984) | 1.22 in (1945) |
| September 30 | 88.0°F (2025) | 34.0°F (1984) | 0.98 in (1986) |