San Luis Weather in September
Average highs run from 77°F on September 1 to 69°F on September 30, and lows from 44°F to 34°F. Normal precipitation for the month is 1.04 in over about 4 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
- 74°F
- Average low
- 39°F
- Precipitation
- 1.04 in
- Record high
- 88°FSep 5, 2013
- Record low
- 18°FSep 30, 1999
- Chance of a freeze
- 78%
- Daylight
- 12 h 58 min to 11 h 50 min
- Cloud cover
- 41%
- Humidity
- 52%
- Dew point
- 36°F
- Wind
- 6.7 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 | 77°F | 44°F | 86°F 2013 | 42°F 2004 | 20% |
| Sep 2 | 77°F | 44°F | 85°F 2012 | 37°F 1993 | 20% |
| Sep 3 | 77°F | 44°F | 85°F 1995 | 37°F 1998 | 20% |
| Sep 4 | 77°F | 43°F | 87°F 1998 | 37°F 2008 | 19% |
| Sep 5 | 76°F | 43°F | 88°F 2013 | 38°F 2008 | 19% |
| Sep 6 | 76°F | 43°F | 86°F 2013 | 37°F 2008 | 18% |
| Sep 7 | 76°F | 42°F | 88°F 2002 | 34°F 2010 | 18% |
| Sep 8 | 76°F | 42°F | 86°F 2002 | 36°F 1998 | 18% |
| Sep 9 | 76°F | 42°F | 84°F 2013 | 28°F 2001 | 17% |
| Sep 10 | 75°F | 42°F | 81°F 2015 | 30°F 2001 | 17% |
| Sep 11 | 75°F | 41°F | 81°F 2018 | 36°F 2016 | 17% |
| Sep 12 | 75°F | 41°F | 82°F 2004 | 35°F 2014 | 16% |
| Sep 13 | 75°F | 40°F | 85°F 1990 | 27°F 1993 | 16% |
| Sep 14 | 74°F | 40°F | 83°F 1990 | 27°F 1993 | 16% |
| Sep 15 | 74°F | 40°F | 83°F 1990 | 35°F 2005 | 15% |
| Sep 16 | 74°F | 39°F | 83°F 2018 | 31°F 1992 | 15% |
| Sep 17 | 73°F | 39°F | 87°F 2000 | 38°F 1992 | 14% |
| Sep 18 | 73°F | 39°F | 84°F 2018 | 34°F 2002 | 14% |
| Sep 19 | 73°F | 38°F | 84°F 2018 | 35°F 1996 | 14% |
| Sep 20 | 73°F | 38°F | 85°F 2010 | 35°F 2015 | 13% |
| Sep 21 | 72°F | 38°F | 80°F 2010 | 25°F 1995 | 13% |
| Sep 22 | 72°F | 37°F | 80°F 2010 | 24°F 1995 | 13% |
| Sep 23 | 72°F | 37°F | 84°F 2018 | 28°F 1991 | 13% |
| Sep 24 | 71°F | 36°F | 79°F 2005 | 27°F 2000 | 12% |
| Sep 25 | 71°F | 36°F | 81°F 2011 | 27°F 2000 | 12% |
| Sep 26 | 71°F | 36°F | 81°F 2011 | 28°F 2000 | 12% |
| Sep 27 | 70°F | 35°F | 81°F 2010 | 25°F 1996 | 12% |
| Sep 28 | 70°F | 35°F | 88°F 1999 | 25°F 1996 | 12% |
| Sep 29 | 70°F | 34°F | 84°F 2010 | 19°F 1999 | 12% |
| Sep 30 | 69°F | 34°F | 81°F 2010 | 18°F 1999 | 11% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (MDT).
- September 1
- sunrise 6:32 AM, sunset 7:30 PM
- September 30
- sunrise 6:56 AM, sunset 6:46 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00057430 (San Luis 1 S), public domain. Records: NOAA GHCN-Daily, station USC00057572, 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.