September weather in Flanagan, IL
The average temperature in Flanagan in September is 66.4°F (53.7°F–79.0°F). Average precipitation: 3.87 inches.
September is a fall month in Flanagan, and is warmer than the annual average of 51.3°F. Daily temperatures swing about 25.3°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
79.0°F
Avg Low
53.7°F
Precipitation
3.87 in
Daylight
12h 15m
September records in Flanagan
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 100.9°F (1953) | 39.9°F (1949) | 4.21 in (1989) |
| September 2 | 102.0°F (1913) | 41.0°F (2017) | 3.97 in (2012) |
| September 3 | 104.0°F (1913) | 39.9°F (1987) | 1.66 in (1993) |
| September 4 | 100.9°F (1925) | 39.0°F (1974) | 2.11 in (1961) |
| September 5 | 104.0°F (1899) | 37.0°F (1974) | 2.71 in (2008) |
| September 6 | 102.9°F (1925) | 39.0°F (1962) | 1.54 in (1898) |
| September 7 | 100.9°F (1939) | 39.0°F (1956) | 2.50 in (1917) |
| September 8 | 99.0°F (1922) | 37.0°F (1986) | 1.81 in (1992) |
| September 9 | 102.0°F (1933) | 42.1°F (1924) | 1.29 in (1989) |
| September 10 | 99.0°F (1912) | 39.0°F (1924) | 2.13 in (2014) |
| September 11 | 98.1°F (1978) | 34.0°F (1917) | 1.30 in (2006) |
| September 12 | 98.1°F (2013) | 39.0°F (1904) | 2.33 in (1961) |
| September 13 | 100.0°F (1939) | 34.0°F (1953) | 2.43 in (2008) |
| September 14 | 100.9°F (1939) | 32.0°F (1923) | 3.35 in (2008) |
| September 15 | 100.9°F (1939) | 32.0°F (2007) | 1.77 in (1903) |
| September 16 | 97.0°F (1939) | 30.0°F (1916) | 1.90 in (1921) |
| September 17 | 95.0°F (1908) | 34.0°F (1918) | 2.45 in (1997) |
| September 18 | 97.0°F (1908) | 32.0°F (1929) | 1.84 in (1904) |
| September 19 | 97.0°F (1908) | 32.0°F (1901) | 2.21 in (1975) |
| September 20 | 97.0°F (1908) | 30.0°F (1918) | 3.85 in (1986) |
| September 21 | 97.0°F (1908) | 33.1°F (1897) | 2.17 in (1950) |
| September 22 | 91.9°F (1930) | 33.1°F (1953) | 3.85 in (2023) |
| September 23 | 95.0°F (2005) | 25.0°F (1974) | 1.76 in (1961) |
| September 24 | 96.1°F (2017) | 28.9°F (1928) | 1.00 in (1945) |
| September 25 | 93.0°F (1908) | 30.0°F (1942) | 4.64 in (1911) |
| September 26 | 95.0°F (2017) | 26.1°F (1928) | 3.87 in (1933) |
| September 27 | 93.9°F (2017) | 30.0°F (1937) | 2.43 in (1907) |
| September 28 | 93.0°F (1939) | 24.1°F (1942) | 9.09 in (2019) |
| September 29 | 98.1°F (1953) | 28.0°F (1899) | 2.39 in (1906) |
| September 30 | 91.9°F (2025) | 21.9°F (1899) | 1.39 in (1896) |