September weather in Great Falls, MT
The average temperature in Great Falls in September is 58.6°F (44.7°F–72.6°F). Average precipitation: 1.39 inches.
September is a fall month in Great Falls, and is warmer than the annual average of 47°F. Daily temperatures swing about 27.9°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
72.6°F
Avg Low
44.7°F
Precipitation
1.39 in
Daylight
12h 19m
September records in Great Falls
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 93.0°F (2016) | 34.0°F (1930) | 1.02 in (1910) |
| September 2 | 96.1°F (2017) | 35.1°F (2008) | 1.14 in (1898) |
| September 3 | 93.0°F (1955) | 35.1°F (1956) | 0.97 in (1909) |
| September 4 | 91.9°F (1919) | 33.1°F (1929) | 0.97 in (2015) |
| September 5 | 95.0°F (1931) | 33.1°F (1956) | 0.54 in (1911) |
| September 6 | 97.0°F (1893) | 27.0°F (1929) | 0.94 in (1924) |
| September 7 | 93.0°F (1955) | 27.0°F (1929) | 0.56 in (1926) |
| September 8 | 91.9°F (1956) | 34.0°F (1910) | 0.81 in (1896) |
| September 9 | 91.9°F (2017) | 32.0°F (1896) | 0.59 in (2019) |
| September 10 | 91.9°F (1956) | 28.9°F (1921) | 0.41 in (1930) |
| September 11 | 93.0°F (1919) | 28.9°F (1921) | 1.05 in (1914) |
| September 12 | 91.9°F (1919) | 30.0°F (1921) | 0.58 in (1893) |
| September 13 | 88.0°F (1953) | 27.0°F (1915) | 0.54 in (2008) |
| September 14 | 91.0°F (1935) | 30.0°F (1903) | 0.95 in (1917) |
| September 15 | 90.0°F (1953) | 28.9°F (1918) | 1.16 in (2017) |
| September 16 | 91.0°F (2009) | 28.0°F (1936) | 0.69 in (2006) |
| September 17 | 91.9°F (2009) | 28.0°F (1902) | 1.27 in (2005) |
| September 18 | 89.1°F (1956) | 30.0°F (1901) | 0.42 in (1900) |
| September 19 | 91.9°F (2009) | 28.0°F (1923) | 1.51 in (1925) |
| September 20 | 93.0°F (1917) | 26.1°F (1934) | 0.28 in (2010) |
| September 21 | 90.0°F (1917) | 27.0°F (1925) | 0.56 in (2016) |
| September 22 | 91.0°F (1896) | 24.1°F (1934) | 0.84 in (1910) |
| September 23 | 91.9°F (2009) | 19.9°F (1934) | 0.85 in (1930) |
| September 24 | 91.0°F (2009) | 10.0°F (1926) | 1.18 in (1918) |
| September 25 | 91.9°F (2014) | 17.1°F (1934) | 0.68 in (1903) |
| September 26 | 89.1°F (2024) | 19.9°F (1934) | 0.65 in (1929) |
| September 27 | 86.0°F (1897) | 24.1°F (1935) | 0.42 in (1915) |
| September 28 | 88.0°F (1892) | 27.0°F (1916) | 0.82 in (2019) |
| September 29 | 90.0°F (1896) | 24.1°F (1919) | 0.73 in (2019) |
| September 30 | 90.0°F (2011) | 27.0°F (2019) | 0.82 in (2009) |