September weather in Pontiac, IL
The average temperature in Pontiac in September is 66.9°F (55.7°F–78.1°F). Average precipitation: 3.39 inches.
September is a fall month in Pontiac, and is warmer than the annual average of 51.8°F. Daily temperatures swing about 22.4°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
78.1°F
Avg Low
55.7°F
Precipitation
3.39 in
Daylight
12h 15m
September records in Pontiac
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 100.0°F (1913) | 42.1°F (2009) | 3.22 in (1926) |
| September 2 | 100.9°F (1913) | 41.0°F (1909) | 2.60 in (1934) |
| September 3 | 100.0°F (1913) | 43.0°F (1908) | 0.84 in (1993) |
| September 4 | 102.9°F (1925) | 46.0°F (1928) | 1.25 in (1991) |
| September 5 | 100.0°F (1925) | 44.1°F (1974) | 3.02 in (2008) |
| September 6 | 102.0°F (1925) | 41.0°F (1988) | 1.65 in (1971) |
| September 7 | 100.9°F (1939) | 43.0°F (1956) | 2.55 in (1917) |
| September 8 | 100.0°F (1922) | 41.0°F (1986) | 1.47 in (1992) |
| September 9 | 100.0°F (1933) | 42.1°F (1986) | 1.47 in (1989) |
| September 10 | 97.0°F (1912) | 39.9°F (1924) | 2.00 in (2014) |
| September 11 | 98.1°F (1931) | 35.1°F (1917) | 1.47 in (1947) |
| September 12 | 97.0°F (1939) | 41.0°F (1917) | 2.79 in (1961) |
| September 13 | 99.0°F (1939) | 39.0°F (1953) | 1.96 in (1970) |
| September 14 | 100.9°F (1939) | 34.0°F (1923) | 3.20 in (2008) |
| September 15 | 100.9°F (1939) | 39.0°F (2007) | 2.66 in (1965) |
| September 16 | 99.0°F (1939) | 30.0°F (1916) | 3.21 in (1921) |
| September 17 | 98.1°F (1927) | 37.9°F (1918) | 1.67 in (1980) |
| September 18 | 95.0°F (1908) | 35.1°F (1929) | 2.37 in (1915) |
| September 19 | 96.1°F (1908) | 37.0°F (1991) | 2.12 in (1975) |
| September 20 | 95.0°F (1908) | 33.1°F (1991) | 2.15 in (1986) |
| September 21 | 95.0°F (1908) | 35.1°F (1991) | 2.77 in (1950) |
| September 22 | 93.0°F (1920) | 36.0°F (1918) | 2.31 in (1970) |
| September 23 | 93.0°F (2005) | 30.9°F (1974) | 3.12 in (1926) |
| September 24 | 93.0°F (1933) | 32.0°F (1928) | 2.64 in (1961) |
| September 25 | 93.9°F (1920) | 32.0°F (1942) | 3.95 in (1911) |
| September 26 | 91.9°F (1920) | 30.9°F (1928) | 4.25 in (1933) |
| September 27 | 91.0°F (1998) | 32.0°F (1942) | 1.85 in (1907) |
| September 28 | 91.0°F (1939) | 26.1°F (1942) | 2.90 in (1927) |
| September 29 | 97.0°F (1953) | 30.9°F (1942) | 1.85 in (1927) |
| September 30 | 91.9°F (1971) | 33.1°F (1930) | 1.22 in (1986) |