Grand County Weather in September
Average highs run from 74°F on September 1 to 65°F on September 30, and lows from 39°F to 30°F. Normal precipitation for the month is 1.40 in over about 8 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
- 70°F
- Average low
- 35°F
- Precipitation
- 1.40 in
- Snowfall
- 0.3 in
- Record high
- 83°FSep 1, 1988
- Record low
- 14°FSep 30, 1959
- Chance of a freeze
- 99%
- Daylight
- 13 h 04 min to 11 h 48 min
- Cloud cover
- 54%
- Humidity
- 52%
- Dew point
- 30°F
- Wind
- 4.5 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 | 74°F | 39°F | 83°F 1988 | 25°F 1956 | 31% | 0% |
| Sep 2 | 74°F | 39°F | 81°F 2002 | 28°F 1959 | 31% | 0% |
| Sep 3 | 74°F | 39°F | 81°F 1998 | 26°F 2006 | 31% | 0% |
| Sep 4 | 74°F | 38°F | 83°F 1998 | 27°F 2008 | 31% | 0% |
| Sep 5 | 73°F | 38°F | 83°F 1998 | 28°F 1950 | 31% | 0% |
| Sep 6 | 73°F | 38°F | 82°F 1978 | 27°F 1956 | 30% | 0% |
| Sep 7 | 73°F | 38°F | 81°F 1978 | 23°F 2010 | 30% | 0% |
| Sep 8 | 73°F | 37°F | 80°F 2022 | 24°F 1948 | 30% | 1% |
| Sep 9 | 72°F | 37°F | 78°F 1979 | 24°F 1962 | 30% | 1% |
| Sep 10 | 72°F | 37°F | 78°F 2021 | 21°F 1962 | 30% | 1% |
| Sep 11 | 72°F | 36°F | 79°F 2021 | 24°F 1948 | 30% | 1% |
| Sep 12 | 72°F | 36°F | 79°F 1990 | 25°F 1948 | 30% | 1% |
| Sep 13 | 71°F | 36°F | 81°F 1990 | 22°F 1951 | 29% | 1% |
| Sep 14 | 71°F | 35°F | 81°F 1990 | 22°F 2003 | 29% | 1% |
| Sep 15 | 71°F | 35°F | 82°F 1990 | 24°F 1979 | 29% | 1% |
| Sep 16 | 70°F | 35°F | 80°F 2000 | 19°F 1951 | 29% | 1% |
| Sep 17 | 70°F | 35°F | 81°F 2000 | 21°F 1951 | 28% | 1% |
| Sep 18 | 70°F | 34°F | 77°F 2004 | 16°F 1971 | 28% | 1% |
| Sep 19 | 69°F | 34°F | 78°F 2014 | 20°F 1971 | 28% | 1% |
| Sep 20 | 69°F | 34°F | 78°F 2010 | 21°F 1975 | 28% | 1% |
| Sep 21 | 69°F | 33°F | 78°F 1966 | 15°F 1983 | 27% | 1% |
| Sep 22 | 68°F | 33°F | 75°F 2001 | 18°F 1995 | 27% | 2% |
| Sep 23 | 68°F | 33°F | 75°F 1949 | 19°F 1956 | 27% | 2% |
| Sep 24 | 67°F | 32°F | 75°F 2015 | 21°F 1956 | 26% | 2% |
| Sep 25 | 67°F | 32°F | 75°F 1948 | 17°F 1961 | 26% | 2% |
| Sep 26 | 67°F | 32°F | 77°F 2024 | 18°F 1970 | 26% | 2% |
| Sep 27 | 66°F | 31°F | 78°F 2001 | 20°F 1973 | 25% | 2% |
| Sep 28 | 66°F | 31°F | 78°F 2001 | 20°F 1959 | 25% | 2% |
| Sep 29 | 65°F | 31°F | 76°F 2010 | 18°F 1988 | 25% | 3% |
| Sep 30 | 65°F | 30°F | 76°F 2024 | 14°F 1959 | 25% | 3% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (MDT).
- September 1
- sunrise 6:32 AM, sunset 7:36 PM
- September 30
- sunrise 7:00 AM, sunset 6:48 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00059096 (Williams Fork Dam), public domain. Records: NOAA GHCN-Daily, station USC00053500, 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.