September weather in Westminster, CO
The average temperature in Westminster in September is 65.2°F (48.9°F–81.5°F). Average precipitation: 1.19 inches.
September is a fall month in Westminster, and is warmer than the annual average of 52.4°F. Daily temperatures swing about 32.6°F between overnight low and afternoon high. Expect about 6 days with precipitation. Daylight averages about 12h 15m. For travel, September is a comfortable month to visit.
Avg High
81.5°F
Avg Low
48.9°F
Precipitation
1.19 in
Snow
0.1 in
September records in Westminster
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 98.1°F (2023) | 46.0°F (2005) | 0.34 in (1990) |
| September 2 | 100.9°F (2019) | 45.0°F (1986) | 0.33 in (1999) |
| September 3 | 102.0°F (2019) | 42.1°F (2006) | 0.04 in (1999) |
| September 4 | 100.0°F (2017) | 34.0°F (1988) | 0.13 in (2023) |
| September 5 | 99.0°F (2002) | 28.0°F (1987) | 0.94 in (2018) |
| September 6 | 100.9°F (2020) | 42.1°F (2025) | 0.12 in (1996) |
| September 7 | 100.9°F (2022) | 41.0°F (2010) | 0.22 in (1986) |
| September 8 | 100.0°F (2022) | 37.0°F (2001) | 0.90 in (2001) |
| September 9 | 102.0°F (2022) | 37.9°F (2001) | 0.51 in (2020) |
| September 10 | 98.1°F (2021) | 39.9°F (1989) | 0.77 in (2013) |
| September 11 | 100.9°F (2021) | 36.0°F (1989) | 0.79 in (2013) |
| September 12 | 100.9°F (1990) | 32.0°F (1989) | 1.88 in (2013) |
| September 13 | 99.0°F (1990) | 30.9°F (1987) | 0.81 in (2013) |
| September 14 | 96.1°F (2018) | 30.0°F (1993) | 0.50 in (1987) |
| September 15 | 93.9°F (1990) | 35.1°F (1988) | 1.65 in (2023) |
| September 16 | 98.1°F (2000) | 36.0°F (1987) | 1.02 in (2013) |
| September 17 | 96.1°F (2021) | 41.0°F (1988) | 0.45 in (2025) |
| September 18 | 93.0°F (2004) | 35.1°F (2003) | 0.71 in (1996) |
| September 19 | 96.1°F (2021) | 30.9°F (1988) | 0.32 in (1997) |
| September 20 | 95.0°F (2022) | 34.0°F (2003) | 0.68 in (2000) |
| September 21 | 96.1°F (2022) | 28.0°F (1995) | 0.40 in (2021) |
| September 22 | 93.9°F (2010) | 26.1°F (1995) | 0.88 in (2024) |
| September 23 | 88.0°F (2007) | 26.1°F (1995) | 0.90 in (2013) |
| September 24 | 90.0°F (2003) | 27.0°F (1985) | 1.26 in (2025) |
| September 25 | 90.0°F (2001) | 30.0°F (1984) | 0.44 in (2007) |
| September 26 | 91.9°F (2001) | 28.9°F (1985) | 0.39 in (2012) |
| September 27 | 96.1°F (2024) | 28.9°F (1996) | 0.14 in (2012) |
| September 28 | 91.0°F (2011) | 19.9°F (1985) | 0.65 in (1999) |
| September 29 | 91.9°F (2024) | 18.0°F (1985) | 0.06 in (2017) |
| September 30 | 95.0°F (2024) | 21.0°F (1985) | 0.89 in (2014) |