September weather in Upland, CA
The average temperature in Upland in September is 77.6°F (63.8°F–91.3°F). Average precipitation: 0.10 inches.
September is a fall month in Upland, and is warmer than the annual average of 66.8°F. Daily temperatures swing about 27.5°F between overnight low and afternoon high. Expect about 1 days with precipitation. Daylight averages about 12h 12m. For travel, September is hot.
Avg High
91.3°F
Avg Low
63.8°F
Precipitation
0.10 in
Daylight
12h 12m
September records in Upland
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 114.1°F (2017) | 57.0°F (2011) | 0.13 in (2023) |
| September 2 | 109.9°F (2007) | 55.9°F (1999) | 0.05 in (2023) |
| September 3 | 109.9°F (2007) | 55.9°F (2000) | 0.02 in (2017) |
| September 4 | 109.0°F (2022) | 57.0°F (1999) | 0.00 in (1998) |
| September 5 | 118.0°F (2020) | 57.0°F (1999) | 0.02 in (2011) |
| September 6 | 117.0°F (2020) | 57.9°F (1999) | 0.00 in (1998) |
| September 7 | 106.0°F (2024) | 55.0°F (1999) | 0.00 in (1998) |
| September 8 | 109.0°F (2024) | 55.0°F (2002) | 0.10 in (2014) |
| September 9 | 108.0°F (2024) | 55.0°F (2000) | 0.47 in (2015) |
| September 10 | 100.0°F (2009) | 55.0°F (2008) | 0.03 in (2023) |
| September 11 | 100.9°F (2017) | 57.0°F (1999) | 0.14 in (2022) |
| September 12 | 105.1°F (2000) | 55.0°F (2005) | 0.00 in (1998) |
| September 13 | 105.1°F (2014) | 55.9°F (2005) | 0.00 in (1998) |
| September 14 | 108.0°F (2014) | 53.1°F (2016) | 0.00 in (1998) |
| September 15 | 107.1°F (2014) | 55.9°F (1999) | 1.25 in (2015) |
| September 16 | 107.1°F (2000) | 55.9°F (1999) | 0.03 in (2002) |
| September 17 | 102.0°F (2000) | 55.0°F (2005) | 0.00 in (1998) |
| September 18 | 106.0°F (2016) | 55.0°F (2010) | 0.09 in (2025) |
| September 19 | 100.0°F (2015) | 55.9°F (2005) | 0.00 in (1998) |
| September 20 | 104.0°F (2015) | 53.1°F (1999) | 0.29 in (2005) |
| September 21 | 105.1°F (2003) | 53.1°F (2007) | 0.00 in (1998) |
| September 22 | 105.1°F (2009) | 54.0°F (2017) | 0.17 in (2007) |
| September 23 | 107.1°F (2002) | 54.0°F (2010) | 0.00 in (1998) |
| September 24 | 102.9°F (2001) | 53.1°F (1998) | 0.02 in (2007) |
| September 25 | 105.1°F (2009) | 52.0°F (2005) | 0.00 in (1998) |
| September 26 | 107.1°F (2010) | 54.0°F (2005) | 0.00 in (1998) |
| September 27 | 111.9°F (2010) | 51.1°F (2013) | 0.03 in (2025) |
| September 28 | 100.0°F (1999) | 52.0°F (1998) | 0.00 in (1998) |
| September 29 | 104.0°F (2020) | 53.1°F (1998) | 0.00 in (1998) |
| September 30 | 108.0°F (2020) | 52.0°F (2019) | 0.00 in (1998) |