September weather in San Luis Obispo, CA
The average temperature in San Luis Obispo in September is 66.4°F (53.4°F–79.5°F). Average precipitation: 0.04 inches.
September is a fall month in San Luis Obispo, and is warmer than the annual average of 59.7°F. Daily temperatures swing about 26.1°F between overnight low and afternoon high. Expect about 1 days with precipitation. Daylight averages about 12h 13m. For travel, September is one of the best months of the year to visit.
Avg High
79.5°F
Avg Low
53.4°F
Precipitation
0.04 in
Daylight
12h 13m
September records in San Luis Obispo
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 106.0°F (2017) | 43.0°F (1999) | 0.00 in (1998) |
| September 2 | 114.1°F (2017) | 51.1°F (1999) | 0.00 in (1998) |
| September 3 | 105.1°F (2022) | 50.0°F (2004) | 0.00 in (1998) |
| September 4 | 102.9°F (2022) | 51.1°F (2000) | 0.20 in (1998) |
| September 5 | 104.0°F (2024) | 48.0°F (2005) | 0.02 in (1998) |
| September 6 | 117.0°F (2020) | 46.0°F (2001) | 0.00 in (1998) |
| September 7 | 108.0°F (2020) | 43.0°F (2002) | 0.00 in (1998) |
| September 8 | 95.0°F (2015) | 44.1°F (2002) | 0.00 in (1998) |
| September 9 | 98.1°F (2015) | 48.0°F (2003) | 0.02 in (2023) |
| September 10 | 97.0°F (2015) | 46.9°F (1998) | 0.14 in (2022) |
| September 11 | 93.0°F (2015) | 46.0°F (1999) | 0.00 in (1998) |
| September 12 | 93.0°F (2015) | 48.9°F (2001) | 0.01 in (1998) |
| September 13 | 100.0°F (2019) | 45.0°F (2018) | 0.00 in (1998) |
| September 14 | 96.1°F (2019) | 45.0°F (2010) | 0.02 in (2015) |
| September 15 | 89.1°F (2009) | 46.9°F (2002) | 0.00 in (1998) |
| September 16 | 91.0°F (2009) | 46.9°F (2020) | 0.00 in (1998) |
| September 17 | 95.0°F (2006) | 46.0°F (2003) | 0.00 in (1998) |
| September 18 | 102.9°F (2016) | 45.0°F (2018) | 0.32 in (2022) |
| September 19 | 99.0°F (2015) | 46.9°F (2002) | 0.54 in (2022) |
| September 20 | 96.1°F (2015) | 44.1°F (1999) | 0.01 in (2003) |
| September 21 | 99.0°F (2015) | 46.0°F (1999) | 0.02 in (2000) |
| September 22 | 91.0°F (1999) | 46.0°F (2010) | 0.18 in (1999) |
| September 23 | 93.0°F (2013) | 45.0°F (2007) | 0.13 in (2025) |
| September 24 | 100.9°F (2015) | 45.0°F (2004) | 0.22 in (2025) |
| September 25 | 105.1°F (2010) | 46.9°F (2005) | 0.01 in (2000) |
| September 26 | 104.0°F (2010) | 46.9°F (1998) | 0.14 in (1998) |
| September 27 | 111.0°F (2010) | 43.0°F (1998) | 0.01 in (1999) |
| September 28 | 109.9°F (2010) | 48.0°F (1998) | 0.02 in (2002) |
| September 29 | 100.0°F (2005) | 42.1°F (2019) | 0.01 in (1998) |
| September 30 | 107.1°F (2020) | 32.0°F (2000) | 0.05 in (2023) |