San Luis Obispo Weather in September
Average highs run from 81°F on September 1 to 79°F on September 30, and lows from 55°F to 53°F. Normal precipitation for the month is 0.11 in over about 1 wet days.
September day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
September at a glance
- Average high
- 80°F
- Average low
- 54°F
- Precipitation
- 0.11 in
- Record high
- 117°FSep 6, 2020
- Record low
- 42°FSep 29, 2019
- Chance of a freeze
- 0%
- Days of 90°F or more
- 4.2
- Daylight
- 12 h 54 min to 11 h 51 min
- Cloud cover
- 22%
- Humidity
- 52%
- Dew point
- 47°F
- Wind
- 6.5 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation.
| Date | Normal high | Normal low | Record high | Record low | Chance wet |
|---|---|---|---|---|---|
| Sep 1 | 81°F | 55°F | 106°F 2017 | 43°F 1999 | 1% |
| Sep 2 | 81°F | 54°F | 114°F 2017 | 51°F 1999 | 1% |
| Sep 3 | 81°F | 54°F | 105°F 2022 | 50°F 2004 | 1% |
| Sep 4 | 81°F | 54°F | 103°F 2022 | 51°F 2000 | 1% |
| Sep 5 | 81°F | 54°F | 104°F 2024 | 48°F 2005 | 1% |
| Sep 6 | 81°F | 54°F | 117°F 2020 | 46°F 2001 | 1% |
| Sep 7 | 81°F | 54°F | 108°F 2020 | 43°F 2002 | 2% |
| Sep 8 | 81°F | 54°F | 95°F 2015 | 44°F 2002 | 2% |
| Sep 9 | 81°F | 54°F | 107°F 2026 | 48°F 2003 | 2% |
| Sep 10 | 81°F | 54°F | 98°F 2026 | 47°F 1998 | 2% |
| Sep 11 | 80°F | 54°F | 93°F 2015 | 46°F 1999 | 2% |
| Sep 12 | 80°F | 54°F | 93°F 2015 | 49°F 2001 | 2% |
| Sep 13 | 80°F | 54°F | 100°F 2019 | 45°F 2018 | 2% |
| Sep 14 | 80°F | 54°F | 96°F 2019 | 45°F 2010 | 2% |
| Sep 15 | 80°F | 54°F | 89°F 2009 | 47°F 2002 | 3% |
| Sep 16 | 80°F | 54°F | 91°F 2009 | 47°F 2020 | 3% |
| Sep 17 | 80°F | 54°F | 95°F 2006 | 46°F 2003 | 3% |
| Sep 18 | 80°F | 54°F | 103°F 2016 | 45°F 2018 | 3% |
| Sep 19 | 80°F | 54°F | 99°F 2015 | 47°F 2002 | 3% |
| Sep 20 | 80°F | 54°F | 96°F 2015 | 44°F 1999 | 4% |
| Sep 21 | 80°F | 54°F | 99°F 2015 | 46°F 1999 | 4% |
| Sep 22 | 80°F | 54°F | 91°F 1999 | 46°F 2010 | 4% |
| Sep 23 | 80°F | 53°F | 93°F 2013 | 45°F 2007 | 4% |
| Sep 24 | 80°F | 53°F | 101°F 2015 | 45°F 2004 | 4% |
| Sep 25 | 80°F | 53°F | 105°F 2010 | 47°F 2005 | 5% |
| Sep 26 | 80°F | 53°F | 104°F 2010 | 47°F 1998 | 5% |
| Sep 27 | 79°F | 53°F | 111°F 2010 | 43°F 1998 | 5% |
| Sep 28 | 79°F | 53°F | 110°F 2010 | 48°F 1998 | 5% |
| Sep 29 | 79°F | 53°F | 100°F 2005 | 42°F 2019 | 5% |
| Sep 30 | 79°F | 53°F | 107°F 2020 | 43°F 2019 | 6% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (PDT).
- September 1
- sunrise 6:35 AM, sunset 7:29 PM
- September 30
- sunrise 6:57 AM, sunset 6:48 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00047851 (San Luis Obispo Poly), public domain. Records: NOAA GHCN-Daily, station USW00093206, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.