September weather in Wilmington, DE
The average temperature in Wilmington in September is 66.8°F (58.6°F–75.0°F). Average precipitation: 5.13 inches.
September is a fall month in Wilmington, and is warmer than the annual average of 53.4°F. Daily temperatures swing about 16.4°F between overnight low and afternoon high. Expect about 9 days with precipitation. Daylight averages about 12h 15m. For travel, September is a wet month.
Avg High
75.0°F
Avg Low
58.6°F
Precipitation
5.13 in
Daylight
12h 15m
September records in Wilmington
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 97.0°F (1932) | 43.0°F (1986) | 3.28 in (2021) |
| September 2 | 96.1°F (1932) | 48.0°F (2008) | 1.89 in (1959) |
| September 3 | 95.0°F (1953) | 48.0°F (1967) | 4.13 in (1969) |
| September 4 | 93.9°F (1985) | 48.9°F (1997) | 1.71 in (1935) |
| September 5 | 91.9°F (1985) | 48.9°F (1974) | 2.82 in (2006) |
| September 6 | 95.0°F (1983) | 48.0°F (1962) | 2.54 in (2008) |
| September 7 | 93.9°F (2023) | 44.1°F (1976) | 2.33 in (2018) |
| September 8 | 95.0°F (1939) | 48.9°F (1944) | 2.67 in (1934) |
| September 9 | 95.0°F (2015) | 48.0°F (1956) | 2.73 in (2018) |
| September 10 | 96.1°F (1983) | 42.1°F (1938) | 2.73 in (2015) |
| September 11 | 97.0°F (1983) | 43.0°F (1976) | 3.75 in (1971) |
| September 12 | 91.0°F (1961) | 46.0°F (1940) | 4.39 in (1960) |
| September 13 | 93.0°F (1952) | 44.1°F (1975) | 6.40 in (1971) |
| September 14 | 89.1°F (1995) | 41.0°F (1975) | 3.60 in (1966) |
| September 15 | 89.1°F (1942) | 41.0°F (1975) | 2.63 in (2003) |
| September 16 | 91.0°F (1970) | 42.1°F (1975) | 9.30 in (1999) |
| September 17 | 91.9°F (1991) | 42.1°F (1975) | 1.97 in (1993) |
| September 18 | 89.1°F (1941) | 41.0°F (1937) | 4.19 in (2004) |
| September 19 | 91.9°F (1983) | 42.1°F (1943) | 1.74 in (1977) |
| September 20 | 90.0°F (1983) | 39.9°F (1979) | 2.49 in (1938) |
| September 21 | 89.1°F (1940) | 37.0°F (1956) | 2.60 in (1966) |
| September 22 | 91.9°F (1970) | 39.9°F (1962) | 2.04 in (1990) |
| September 23 | 93.9°F (1970) | 37.0°F (1947) | 2.50 in (1975) |
| September 24 | 91.0°F (1970) | 35.1°F (1974) | 2.60 in (1946) |
| September 25 | 91.0°F (1970) | 37.9°F (1963) | 2.17 in (1991) |
| September 26 | 89.1°F (1970) | 35.1°F (1940) | 1.66 in (1993) |
| September 27 | 89.1°F (1998) | 32.0°F (1940) | 2.89 in (1985) |
| September 28 | 88.0°F (1998) | 35.1°F (1947) | 4.69 in (2004) |
| September 29 | 88.0°F (1945) | 34.0°F (1942) | 2.86 in (2016) |
| September 30 | 88.0°F (1986) | 34.0°F (1942) | 3.10 in (2010) |