September weather in St. Ignatius, MT
The average temperature in St. Ignatius in September is 59.4°F (44.1°F–74.8°F). Average precipitation: 1.51 inches.
September is a fall month in St. Ignatius, and is warmer than the annual average of 47.7°F. Daily temperatures swing about 30.7°F between overnight low and afternoon high. Expect about 7 days with precipitation. Daylight averages about 12h 19m. For travel, September is a comfortable month to visit.
Avg High
74.8°F
Avg Low
44.1°F
Precipitation
1.51 in
Daylight
12h 19m
September records in St. Ignatius
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 98.1°F (1967) | 25.0°F (2021) | 0.83 in (1910) |
| September 2 | 98.1°F (1967) | 25.0°F (2021) | 1.71 in (1968) |
| September 3 | 95.0°F (1998) | 30.9°F (1973) | 0.91 in (1916) |
| September 4 | 98.1°F (1998) | 28.0°F (1929) | 0.99 in (1911) |
| September 5 | 95.0°F (1998) | 30.9°F (1956) | 0.79 in (1996) |
| September 6 | 91.9°F (1957) | 23.0°F (1929) | 0.77 in (1911) |
| September 7 | 93.0°F (1998) | 25.0°F (1929) | 0.56 in (1978) |
| September 8 | 91.9°F (2022) | 28.9°F (1927) | 0.92 in (1995) |
| September 9 | 91.9°F (2005) | 30.0°F (1896) | 1.17 in (1931) |
| September 10 | 88.0°F (1953) | 28.0°F (1929) | 1.19 in (1942) |
| September 11 | 91.0°F (1953) | 28.9°F (1989) | 0.69 in (1949) |
| September 12 | 91.9°F (2022) | 27.0°F (1915) | 1.53 in (1985) |
| September 13 | 86.0°F (1943) | 28.0°F (1974) | 0.71 in (1897) |
| September 14 | 87.1°F (1935) | 23.0°F (1921) | 0.42 in (1973) |
| September 15 | 93.0°F (1998) | 27.0°F (1970) | 1.86 in (1959) |
| September 16 | 90.0°F (1998) | 25.0°F (1973) | 0.98 in (1947) |
| September 17 | 90.0°F (1920) | 21.0°F (1965) | 0.78 in (2006) |
| September 18 | 88.0°F (1984) | 25.0°F (1971) | 1.40 in (1989) |
| September 19 | 87.1°F (1922) | 27.0°F (1926) | 0.95 in (1925) |
| September 20 | 90.0°F (1922) | 23.0°F (1983) | 0.66 in (2021) |
| September 21 | 91.0°F (1967) | 24.1°F (1971) | 0.77 in (1931) |
| September 22 | 90.0°F (1967) | 26.1°F (1971) | 1.03 in (2022) |
| September 23 | 84.9°F (1990) | 25.0°F (1929) | 1.70 in (1930) |
| September 24 | 86.0°F (1990) | 3.9°F (1926) | 1.09 in (2005) |
| September 25 | 86.0°F (1974) | 12.9°F (1926) | 0.34 in (1929) |
| September 26 | 89.1°F (1952) | 19.9°F (1926) | 0.31 in (1982) |
| September 27 | 89.1°F (1957) | 26.1°F (1924) | 0.80 in (1915) |
| September 28 | 88.0°F (1967) | 21.9°F (1999) | 0.73 in (1982) |
| September 29 | 87.1°F (1967) | 21.9°F (1984) | 0.54 in (1977) |
| September 30 | 84.9°F (1963) | 19.0°F (1985) | 0.57 in (1967) |