September weather in Fairfield, IL
The average temperature in Fairfield in September is 70.2°F (57.9°F–82.6°F). Average precipitation: 2.90 inches.
September is a fall month in Fairfield, and is warmer than the annual average of 57.1°F. Daily temperatures swing about 24.7°F between overnight low and afternoon high. Expect about 7 days with precipitation. Daylight averages about 12h 14m. For travel, September is a comfortable month to visit.
Avg High
82.6°F
Avg Low
57.9°F
Precipitation
2.90 in
Daylight
12h 14m
September records in Fairfield
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 102.9°F (1943) | 45.0°F (1987) | 3.36 in (1931) |
| September 2 | 100.9°F (1913) | 45.0°F (1965) | 2.97 in (1931) |
| September 3 | 102.9°F (1913) | 45.0°F (1952) | 4.05 in (1926) |
| September 4 | 102.0°F (1925) | 43.0°F (1952) | 1.23 in (1991) |
| September 5 | 104.0°F (1925) | 42.1°F (1902) | 2.27 in (1911) |
| September 6 | 104.0°F (1925) | 42.1°F (1988) | 2.66 in (1910) |
| September 7 | 102.9°F (1939) | 39.9°F (1988) | 1.35 in (1990) |
| September 8 | 104.0°F (1939) | 39.9°F (1956) | 3.84 in (2018) |
| September 9 | 102.9°F (1939) | 43.0°F (1956) | 3.31 in (1976) |
| September 10 | 100.9°F (1938) | 39.9°F (1924) | 2.52 in (1974) |
| September 11 | 99.0°F (1908) | 39.0°F (1917) | 2.00 in (1965) |
| September 12 | 100.9°F (1939) | 39.0°F (1940) | 2.10 in (1949) |
| September 13 | 102.9°F (1939) | 37.0°F (1902) | 2.70 in (1943) |
| September 14 | 104.0°F (1939) | 33.1°F (1902) | 2.18 in (1962) |
| September 15 | 105.1°F (1939) | 36.0°F (1902) | 1.59 in (1913) |
| September 16 | 98.1°F (1927) | 36.0°F (1916) | 1.90 in (1918) |
| September 17 | 98.1°F (1931) | 37.0°F (1937) | 2.38 in (2016) |
| September 18 | 98.1°F (1935) | 35.1°F (1901) | 1.90 in (2011) |
| September 19 | 98.1°F (1940) | 32.0°F (1901) | 1.80 in (1896) |
| September 20 | 98.1°F (1940) | 35.1°F (1991) | 2.24 in (1954) |
| September 21 | 100.0°F (1940) | 36.0°F (1918) | 1.92 in (1947) |
| September 22 | 99.0°F (1940) | 33.1°F (1983) | 2.01 in (1993) |
| September 23 | 98.1°F (2007) | 32.0°F (1983) | 1.51 in (2025) |
| September 24 | 97.0°F (1935) | 32.0°F (1928) | 2.40 in (2009) |
| September 25 | 93.9°F (1908) | 34.0°F (1965) | 2.20 in (2011) |
| September 26 | 93.9°F (1897) | 30.9°F (1928) | 2.09 in (2012) |
| September 27 | 97.0°F (1905) | 32.0°F (1899) | 1.73 in (1959) |
| September 28 | 97.0°F (1939) | 28.9°F (1942) | 2.20 in (1916) |
| September 29 | 99.0°F (1953) | 30.9°F (1942) | 1.96 in (1974) |
| September 30 | 93.9°F (1919) | 25.0°F (1899) | 3.50 in (1926) |