September weather in Boulder, UT
The average temperature in Boulder in September is 63.0°F (52.0°F–74.0°F). Average precipitation: 1.58 inches.
September is a fall month in Boulder, and is warmer than the annual average of 50.3°F. Daily temperatures swing about 22°F between overnight low and afternoon high. Expect about 7 days with precipitation. Daylight averages about 12h 14m. For travel, September is one of the best months of the year to visit.
Avg High
74.0°F
Avg Low
52.0°F
Precipitation
1.58 in
Daylight
12h 14m
September records in Boulder
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 90.0°F (1958) | 44.1°F (1959) | 1.72 in (2021) |
| September 2 | 90.0°F (2022) | 34.0°F (1973) | 0.91 in (2012) |
| September 3 | 89.1°F (1990) | 34.0°F (1961) | 0.71 in (2005) |
| September 4 | 88.0°F (2017) | 35.1°F (1971) | 0.71 in (2007) |
| September 5 | 91.0°F (2022) | 39.9°F (2004) | 1.42 in (1981) |
| September 6 | 93.0°F (2020) | 36.0°F (1970) | 1.65 in (1991) |
| September 7 | 89.1°F (2022) | 42.1°F (1962) | 0.71 in (2002) |
| September 8 | 89.1°F (2022) | 41.0°F (1971) | 0.61 in (1961) |
| September 9 | 87.1°F (1979) | 32.0°F (1962) | 1.00 in (1980) |
| September 10 | 88.0°F (1990) | 35.1°F (2020) | 0.60 in (1980) |
| September 11 | 88.0°F (1990) | 37.0°F (1957) | 1.88 in (2013) |
| September 12 | 87.1°F (1971) | 33.1°F (1985) | 0.85 in (1958) |
| September 13 | 89.1°F (1990) | 30.9°F (1988) | 0.63 in (1996) |
| September 14 | 88.0°F (1990) | 35.1°F (1982) | 1.06 in (2011) |
| September 15 | 86.0°F (1956) | 37.9°F (1966) | 1.04 in (1997) |
| September 16 | 86.0°F (1983) | 35.1°F (1968) | 0.91 in (2001) |
| September 17 | 87.1°F (2000) | 32.0°F (1968) | 0.45 in (1961) |
| September 18 | 86.0°F (1956) | 24.1°F (1971) | 1.06 in (1963) |
| September 19 | 87.1°F (1956) | 28.0°F (1978) | 1.03 in (2004) |
| September 20 | 82.0°F (2001) | 27.0°F (1978) | 0.65 in (1962) |
| September 21 | 84.9°F (1991) | 28.0°F (1978) | 1.92 in (1962) |
| September 22 | 84.0°F (2001) | 32.0°F (1968) | 0.32 in (1967) |
| September 23 | 82.9°F (1966) | 32.0°F (1968) | 2.20 in (2016) |
| September 24 | 84.0°F (1982) | 26.1°F (2000) | 0.46 in (1990) |
| September 25 | 82.0°F (2001) | 25.0°F (1958) | 0.71 in (1967) |
| September 26 | 82.0°F (1956) | 28.9°F (1970) | 0.50 in (1997) |
| September 27 | 84.0°F (1963) | 32.0°F (1996) | 0.72 in (2014) |
| September 28 | 84.0°F (1963) | 24.1°F (1959) | 0.71 in (1962) |
| September 29 | 82.0°F (1969) | 30.9°F (1985) | 0.95 in (2002) |
| September 30 | 84.0°F (2024) | 28.9°F (2007) | 1.41 in (1983) |