September weather in Wilmington, IL
The average temperature in Wilmington in September is 67.0°F (55.1°F–78.9°F). Average precipitation: 2.99 inches.
September is a fall month in Wilmington, and is warmer than the annual average of 52.9°F. Daily temperatures swing about 23.8°F between overnight low and afternoon high. Expect about 8 days with precipitation. Daylight averages about 12h 15m. For travel, September is one of the best months of the year to visit.
Avg High
78.9°F
Avg Low
55.1°F
Precipitation
2.99 in
Daylight
12h 15m
September records in Wilmington
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 102.9°F (1913) | 41.0°F (1915) | 2.88 in (2012) |
| September 2 | 102.0°F (1913) | 45.0°F (1919) | 1.80 in (1914) |
| September 3 | 100.9°F (1925) | 39.9°F (1952) | 1.74 in (1993) |
| September 4 | 102.9°F (1925) | 42.1°F (1928) | 5.39 in (1926) |
| September 5 | 102.9°F (1925) | 46.0°F (1974) | 2.24 in (1921) |
| September 6 | 104.0°F (1913) | 41.0°F (1988) | 1.06 in (1895) |
| September 7 | 100.0°F (1922) | 41.0°F (2017) | 1.27 in (1911) |
| September 8 | 100.0°F (1947) | 36.0°F (1986) | 0.90 in (1917) |
| September 9 | 102.0°F (1925) | 37.0°F (1986) | 1.95 in (1984) |
| September 10 | 100.0°F (1919) | 39.9°F (1898) | 1.30 in (1905) |
| September 11 | 100.0°F (1936) | 35.1°F (1917) | 2.50 in (1975) |
| September 12 | 98.1°F (1939) | 35.1°F (1955) | 1.76 in (1949) |
| September 13 | 99.0°F (1936) | 37.9°F (1902) | 2.00 in (1945) |
| September 14 | 100.0°F (1939) | 35.1°F (1923) | 2.40 in (2008) |
| September 15 | 100.9°F (1939) | 37.9°F (1916) | 1.50 in (1915) |
| September 16 | 99.0°F (1939) | 33.1°F (1916) | 3.77 in (1965) |
| September 17 | 97.0°F (1925) | 33.1°F (1937) | 1.41 in (1969) |
| September 18 | 99.0°F (1925) | 35.1°F (1916) | 1.90 in (1904) |
| September 19 | 98.1°F (1925) | 39.0°F (1991) | 3.29 in (1975) |
| September 20 | 97.0°F (1931) | 32.0°F (1918) | 2.00 in (1986) |
| September 21 | 97.0°F (1940) | 32.0°F (1918) | 3.65 in (2009) |
| September 22 | 96.1°F (1956) | 30.0°F (1913) | 1.78 in (1970) |
| September 23 | 93.9°F (2017) | 33.1°F (1983) | 3.00 in (1910) |
| September 24 | 93.0°F (2007) | 34.0°F (1942) | 1.37 in (1921) |
| September 25 | 91.9°F (2017) | 33.1°F (1950) | 2.34 in (1941) |
| September 26 | 91.9°F (2017) | 27.0°F (1928) | 2.00 in (1942) |
| September 27 | 91.0°F (2017) | 30.0°F (1942) | 2.99 in (1936) |
| September 28 | 97.0°F (1953) | 25.0°F (1942) | 1.86 in (1936) |
| September 29 | 102.0°F (1953) | 30.9°F (1908) | 2.46 in (1934) |
| September 30 | 100.0°F (1953) | 32.0°F (1912) | 1.48 in (1926) |