San Luis Weather in September
Average highs run from 105°F on September 1 to 96°F on September 30, and lows from 82°F to 72°F. Normal precipitation for the month is 0.68 in over about 2 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
- 101°F
- Average low
- 78°F
- Precipitation
- 0.68 in
- Record high
- 120°FSep 5, 2020
- Record low
- 55°FSep 24, 1986
- Chance of a freeze
- 0%
- Days of 90°F or more
- 28.8
- Daylight
- 12 h 49 min to 11 h 52 min
- Cloud cover
- 29%
- Humidity
- 32%
- Dew point
- 51°F
- Wind
- 6.0 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 | 105°F | 82°F | 115°F 1982 | 73°F 1992 | 6% |
| Sep 2 | 105°F | 82°F | 115°F 1982 | 73°F 1986 | 6% |
| Sep 3 | 105°F | 81°F | 115°F 2010 | 75°F 1985 | 6% |
| Sep 4 | 105°F | 81°F | 115°F 2024 | 67°F 1985 | 6% |
| Sep 5 | 105°F | 81°F | 120°F 2020 | 68°F 2004 | 6% |
| Sep 6 | 104°F | 81°F | 115°F 2020 | 71°F 1985 | 6% |
| Sep 7 | 104°F | 81°F | 112°F 1994 | 67°F 1985 | 5% |
| Sep 8 | 104°F | 80°F | 113°F 1993 | 71°F 2010 | 5% |
| Sep 9 | 104°F | 80°F | 113°F 1990 | 70°F 1989 | 5% |
| Sep 10 | 103°F | 80°F | 115°F 1990 | 66°F 1989 | 5% |
| Sep 11 | 103°F | 79°F | 116°F 1990 | 65°F 1985 | 5% |
| Sep 12 | 103°F | 79°F | 111°F 1995 | 62°F 1985 | 5% |
| Sep 13 | 103°F | 79°F | 111°F 1995 | 66°F 1985 | 5% |
| Sep 14 | 102°F | 79°F | 113°F 2018 | 65°F 1987 | 5% |
| Sep 15 | 102°F | 78°F | 111°F 2018 | 68°F 2016 | 5% |
| Sep 16 | 102°F | 78°F | 111°F 2013 | 66°F 1982 | 4% |
| Sep 17 | 101°F | 77°F | 112°F 2020 | 65°F 1982 | 4% |
| Sep 18 | 101°F | 77°F | 109°F 1984 | 58°F 1985 | 4% |
| Sep 19 | 101°F | 77°F | 113°F 2010 | 63°F 1985 | 4% |
| Sep 20 | 100°F | 76°F | 108°F 1984 | 60°F 1989 | 4% |
| Sep 21 | 100°F | 76°F | 108°F 2003 | 63°F 1986 | 4% |
| Sep 22 | 99°F | 76°F | 110°F 1982 | 64°F 1988 | 4% |
| Sep 23 | 99°F | 75°F | 111°F 1992 | 61°F 1986 | 4% |
| Sep 24 | 99°F | 75°F | 110°F 2024 | 55°F 1986 | 4% |
| Sep 25 | 98°F | 74°F | 110°F 2015 | 61°F 2017 | 4% |
| Sep 26 | 98°F | 74°F | 111°F 2010 | 59°F 1986 | 3% |
| Sep 27 | 98°F | 74°F | 110°F 2009 | 61°F 1986 | 3% |
| Sep 28 | 97°F | 73°F | 112°F 2024 | 57°F 1982 | 3% |
| Sep 29 | 97°F | 73°F | 109°F 2024 | 62°F 1986 | 3% |
| Sep 30 | 96°F | 72°F | 109°F 2012 | 58°F 2019 | 3% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (MST).
- September 1
- sunrise 6:14 AM, sunset 7:03 PM
- September 30
- sunrise 6:33 AM, sunset 6:25 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USW00003145 (Yuma Mcas), public domain. Records: NOAA GHCN-Daily, station USW00003145, 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.