September weather in Waterloo, IL
The average temperature in Waterloo in September is °F (°F–°F). Average precipitation: 3.94 inches.
September is a fall month in Waterloo, and is cooler than the annual average of 0°F. Expect about 6 days with precipitation. Daylight averages about 12h 14m.
Avg High
°F
Avg Low
°F
Precipitation
3.94 in
Daylight
12h 14m
September records in Waterloo
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 97.0°F (1980) | 45.0°F (1967) | 1.53 in (1959) |
| September 2 | 100.0°F (1984) | 46.0°F (1967) | 2.12 in (1980) |
| September 3 | 95.0°F (1977) | 46.9°F (1974) | 1.44 in (1926) |
| September 4 | 93.9°F (1975) | 45.0°F (1974) | 1.80 in (2008) |
| September 5 | 96.1°F (1976) | 48.0°F (1974) | 2.30 in (2008) |
| September 6 | 98.1°F (1964) | 44.1°F (1988) | 1.45 in (2009) |
| September 7 | 99.0°F (1983) | 46.0°F (1966) | 1.57 in (1996) |
| September 8 | 98.1°F (1971) | 42.1°F (1986) | 1.22 in (1913) |
| September 9 | 96.1°F (1980) | 46.0°F (1966) | 3.50 in (1973) |
| September 10 | 95.0°F (1947) | 44.1°F (1976) | 1.76 in (1950) |
| September 11 | 96.1°F (1983) | 46.0°F (1976) | 2.88 in (1984) |
| September 12 | 91.0°F (1972) | 43.0°F (1968) | 2.45 in (1949) |
| September 13 | 96.1°F (1971) | 42.1°F (1964) | 2.14 in (1949) |
| September 14 | 102.0°F (1971) | 44.1°F (1964) | 2.05 in (1989) |
| September 15 | 99.0°F (1971) | 42.1°F (1979) | 1.37 in (1914) |
| September 16 | 93.0°F (1991) | 42.1°F (1966) | 1.81 in (1918) |
| September 17 | 93.0°F (1997) | 43.0°F (1966) | 2.31 in (1970) |
| September 18 | 93.9°F (1978) | 39.0°F (1981) | 5.08 in (1986) |
| September 19 | 95.0°F (1972) | 37.9°F (1991) | 2.62 in (1988) |
| September 20 | 95.0°F (1978) | 37.0°F (1991) | 2.21 in (1924) |
| September 21 | 95.0°F (1978) | 37.0°F (1983) | 1.77 in (1967) |
| September 22 | 91.9°F (2010) | 36.0°F (1995) | 1.88 in (1965) |
| September 23 | 91.0°F (1980) | 34.0°F (1983) | 3.40 in (1984) |
| September 24 | 90.0°F (2010) | 37.0°F (1989) | 1.85 in (1961) |
| September 25 | 88.0°F (1986) | 37.0°F (1989) | 1.83 in (1941) |
| September 26 | 90.0°F (1971) | 37.0°F (1984) | 3.51 in (1925) |
| September 27 | 91.0°F (1998) | 37.9°F (1985) | 3.96 in (1981) |
| September 28 | 90.0°F (1971) | 37.9°F (1967) | 1.42 in (2024) |
| September 29 | 91.0°F (1971) | 37.9°F (1967) | 1.41 in (2005) |
| September 30 | 91.9°F (1971) | 34.0°F (1984) | 1.25 in (1929) |