September weather in Fountain Valley, CA
The average temperature in Fountain Valley in September is 72.5°F (65.0°F–79.9°F). Average precipitation: 0.10 inches.
September is a fall month in Fountain Valley, and is warmer than the annual average of 64.9°F. Daily temperatures swing about 14.9°F between overnight low and afternoon high. Expect about 1 days with precipitation. Daylight averages about 12h 12m. For travel, September is one of the best months of the year to visit.
Avg High
79.9°F
Avg Low
65.0°F
Precipitation
0.10 in
Daylight
12h 12m
September records in Fountain Valley
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 96.1°F (2017) | 62.1°F (1999) | 0.00 in (1999) |
| September 2 | 93.9°F (2007) | 60.1°F (2011) | 0.01 in (2004) |
| September 3 | 99.0°F (2007) | 60.1°F (2010) | 0.00 in (1999) |
| September 4 | 106.0°F (2022) | 60.1°F (2010) | 0.00 in (1999) |
| September 5 | 104.0°F (2020) | 60.1°F (2000) | 0.00 in (1999) |
| September 6 | 109.0°F (2024) | 61.0°F (2000) | 0.00 in (1999) |
| September 7 | 99.0°F (2022) | 62.1°F (1999) | 0.00 in (1999) |
| September 8 | 102.0°F (2022) | 57.9°F (2002) | 0.00 in (1999) |
| September 9 | 102.0°F (2022) | 59.0°F (2000) | 0.29 in (2015) |
| September 10 | 93.0°F (2015) | 60.1°F (1999) | 0.07 in (2011) |
| September 11 | 91.0°F (2000) | 59.0°F (2000) | 0.08 in (2022) |
| September 12 | 91.0°F (2015) | 60.1°F (1999) | 0.00 in (1999) |
| September 13 | 91.0°F (2014) | 60.1°F (2005) | 0.00 in (1999) |
| September 14 | 99.0°F (2012) | 60.1°F (1999) | 0.00 in (1999) |
| September 15 | 102.0°F (2012) | 59.0°F (2002) | 1.49 in (2015) |
| September 16 | 100.0°F (2014) | 59.0°F (2002) | 0.00 in (1999) |
| September 17 | 93.9°F (2014) | 59.0°F (2005) | 0.00 in (1999) |
| September 18 | 90.0°F (2020) | 60.1°F (2006) | 0.00 in (1999) |
| September 19 | 87.1°F (2016) | 60.1°F (1999) | 0.08 in (2005) |
| September 20 | 98.1°F (2015) | 57.0°F (1999) | 0.13 in (2005) |
| September 21 | 96.1°F (2021) | 55.9°F (2007) | 0.38 in (2007) |
| September 22 | 93.0°F (2004) | 59.0°F (2005) | 0.23 in (2007) |
| September 23 | 98.1°F (2009) | 57.9°F (2017) | 0.00 in (1999) |
| September 24 | 91.0°F (2001) | 57.0°F (2017) | 0.10 in (2021) |
| September 25 | 102.0°F (2016) | 57.0°F (2005) | 0.00 in (1999) |
| September 26 | 106.0°F (2016) | 59.0°F (2005) | 0.00 in (1999) |
| September 27 | 109.9°F (2010) | 57.0°F (2013) | 0.00 in (1999) |
| September 28 | 102.0°F (2005) | 57.0°F (2013) | 0.03 in (2019) |
| September 29 | 97.0°F (1999) | 57.0°F (1999) | 0.01 in (2008) |
| September 30 | 100.0°F (2020) | 57.0°F (2007) | 0.01 in (2006) |