Basin Weather in September
Average highs run from 86°F on September 1 to 72°F on September 30, and lows from 52°F to 42°F. Normal precipitation for the month is 0.95 in over about 5 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
- 79°F
- Average low
- 48°F
- Precipitation
- 0.95 in
- Snowfall
- 0.2 in
- Record high
- 103°FSep 4, 2022
- Record low
- 27°FSep 18, 2003
- Chance of a freeze
- 18%
- Days of 90°F or more
- 4.3
- Daylight
- 13 h 13 min to 11 h 45 min
- Cloud cover
- 47%
- Humidity
- 43%
- Dew point
- 36°F
- Wind
- 7.2 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.
| Date | Normal high | Normal low | Record high | Record low | Chance wet | Chance of snow |
|---|---|---|---|---|---|---|
| Sep 1 | 86°F | 52°F | 100°F 2022 | 40°F 2020 | 14% | 0% |
| Sep 2 | 86°F | 52°F | 99°F 2024 | 37°F 2006 | 14% | 0% |
| Sep 3 | 85°F | 52°F | 99°F 2022 | 35°F 2006 | 14% | 0% |
| Sep 4 | 85°F | 51°F | 103°F 2022 | 38°F 2006 | 14% | 0% |
| Sep 5 | 84°F | 51°F | 99°F 2020 | 40°F 2008 | 14% | 0% |
| Sep 6 | 84°F | 51°F | 94°F 2022 | 39°F 2025 | 14% | 0% |
| Sep 7 | 84°F | 51°F | 103°F 2022 | 34°F 2010 | 15% | 0% |
| Sep 8 | 83°F | 50°F | 93°F 2005 | 34°F 2008 | 15% | 0% |
| Sep 9 | 83°F | 50°F | 97°F 2021 | 29°F 2020 | 15% | 0% |
| Sep 10 | 82°F | 50°F | 94°F 2021 | 33°F 2007 | 15% | 0% |
| Sep 11 | 82°F | 49°F | 91°F 2017 | 35°F 2007 | 15% | 0% |
| Sep 12 | 81°F | 49°F | 93°F 2017 | 32°F 1999 | 15% | 0% |
| Sep 13 | 81°F | 49°F | 92°F 2015 | 31°F 1999 | 16% | 0% |
| Sep 14 | 80°F | 48°F | 90°F 2015 | 35°F 2003 | 16% | 0% |
| Sep 15 | 80°F | 48°F | 96°F 2000 | 35°F 2003 | 16% | 0% |
| Sep 16 | 79°F | 48°F | 96°F 2000 | 38°F 1999 | 16% | 1% |
| Sep 17 | 79°F | 47°F | 89°F 2004 | 34°F 2003 | 16% | 1% |
| Sep 18 | 78°F | 47°F | 90°F 2004 | 27°F 2003 | 16% | 1% |
| Sep 19 | 78°F | 46°F | 92°F 2010 | 30°F 2003 | 16% | 1% |
| Sep 20 | 77°F | 46°F | 86°F 2005 | 31°F 1999 | 16% | 1% |
| Sep 21 | 77°F | 46°F | 86°F 2013 | 32°F 1999 | 16% | 1% |
| Sep 22 | 76°F | 45°F | 90°F 2007 | 29°F 2000 | 16% | 1% |
| Sep 23 | 76°F | 45°F | 89°F 2015 | 29°F 2000 | 16% | 1% |
| Sep 24 | 75°F | 45°F | 92°F 2020 | 28°F 2000 | 16% | 1% |
| Sep 25 | 75°F | 44°F | 94°F 2024 | 28°F 2000 | 16% | 1% |
| Sep 26 | 74°F | 44°F | 97°F 2015 | 29°F 2000 | 16% | 1% |
| Sep 27 | 73°F | 43°F | 91°F 2001 | 33°F 2000 | 16% | 1% |
| Sep 28 | 73°F | 43°F | 92°F 2001 | 28°F 1999 | 16% | 1% |
| Sep 29 | 72°F | 43°F | 97°F 2024 | 27°F 1999 | 16% | 1% |
| Sep 30 | 72°F | 42°F | 86°F 2015 | 29°F 2021 | 16% | 1% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (MDT).
- September 1
- sunrise 6:35 AM, sunset 7:48 PM
- September 30
- sunrise 7:09 AM, sunset 6:54 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00480540 (Basin), public domain. Records: NOAA GHCN-Daily, station USW00024048, 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.