September weather in Grass Range, MT
The average temperature in Grass Range in September is 58.0°F (43.5°F–72.6°F). Average precipitation: 1.46 inches.
September is a fall month in Grass Range, and is warmer than the annual average of 45.5°F. Daily temperatures swing about 29.1°F between overnight low and afternoon high. Expect about 6 days with precipitation. Daylight averages about 12h 19m. For travel, September is a comfortable month to visit.
Avg High
72.6°F
Avg Low
43.5°F
Precipitation
1.46 in
Snow
0.1 in
September records in Grass Range
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 99.0°F (1983) | 36.0°F (1954) | 1.20 in (1973) |
| September 2 | 99.0°F (1945) | 30.0°F (1914) | 0.25 in (1951) |
| September 3 | 99.0°F (2022) | 28.0°F (1959) | 0.49 in (1963) |
| September 4 | 100.0°F (1950) | 25.0°F (1956) | 0.46 in (1936) |
| September 5 | 98.1°F (1976) | 30.0°F (1956) | 1.73 in (2016) |
| September 6 | 98.1°F (1980) | 26.1°F (1956) | 0.64 in (2002) |
| September 7 | 100.0°F (2022) | 30.9°F (1972) | 2.06 in (1941) |
| September 8 | 98.1°F (1979) | 25.0°F (1943) | 0.64 in (1977) |
| September 9 | 98.1°F (1981) | 23.0°F (1962) | 0.76 in (1946) |
| September 10 | 91.9°F (1968) | 28.0°F (1945) | 0.76 in (1961) |
| September 11 | 93.0°F (1966) | 21.0°F (1989) | 0.72 in (1988) |
| September 12 | 97.0°F (1953) | 19.9°F (1989) | 2.28 in (1978) |
| September 13 | 93.0°F (1959) | 26.1°F (1970) | 0.85 in (1954) |
| September 14 | 96.1°F (1948) | 18.0°F (1970) | 0.86 in (1934) |
| September 15 | 93.0°F (1979) | 26.1°F (1970) | 1.83 in (2017) |
| September 16 | 93.9°F (1998) | 25.0°F (1970) | 1.32 in (1946) |
| September 17 | 91.0°F (1943) | 25.0°F (1965) | 0.71 in (2010) |
| September 18 | 96.1°F (1981) | 19.0°F (1965) | 2.37 in (2024) |
| September 19 | 97.0°F (1981) | 21.9°F (1915) | 0.39 in (2000) |
| September 20 | 90.0°F (1938) | 26.1°F (1978) | 0.82 in (1970) |
| September 21 | 93.0°F (1936) | 17.1°F (1995) | 1.47 in (1959) |
| September 22 | 93.9°F (1938) | 21.9°F (1961) | 1.24 in (1959) |
| September 23 | 90.0°F (1966) | 21.9°F (1934) | 1.16 in (1941) |
| September 24 | 91.9°F (1938) | 21.0°F (1934) | 0.65 in (2007) |
| September 25 | 91.9°F (2015) | 19.0°F (1934) | 0.92 in (1986) |
| September 26 | 91.9°F (1963) | 18.0°F (1972) | 0.39 in (2013) |
| September 27 | 91.0°F (1963) | 19.9°F (1945) | 1.55 in (1982) |
| September 28 | 90.0°F (1938) | 19.0°F (1984) | 1.22 in (2019) |
| September 29 | 90.0°F (1989) | 18.0°F (1959) | 2.13 in (2019) |
| September 30 | 93.0°F (1963) | 15.1°F (1985) | 0.70 in (1977) |