Dillon Weather in September
Average highs run from 76°F on September 1 to 65°F on September 30, and lows from 42°F to 36°F. Normal precipitation for the month is 0.89 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
- 71°F
- Average low
- 39°F
- Precipitation
- 0.89 in
- Record high
- 97°FSep 3, 2022
- Record low
- 10°FSep 20, 1983
- Chance of a freeze
- 93%
- Days of 90°F or more
- 0.5
- Daylight
- 13 h 15 min to 11 h 44 min
- Cloud cover
- 48%
- Humidity
- 54%
- Dew point
- 32°F
- Wind
- 6.5 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 | 76°F | 42°F | 92°F 1950 | 32°F 2006 | 18% | 0% |
| Sep 2 | 76°F | 42°F | 93°F 1950 | 25°F 1974 | 18% | 0% |
| Sep 3 | 76°F | 42°F | 97°F 2022 | 30°F 1958 | 18% | 0% |
| Sep 4 | 75°F | 42°F | 92°F 1950 | 32°F 1951 | 18% | 0% |
| Sep 5 | 75°F | 42°F | 92°F 1976 | 27°F 1956 | 18% | 0% |
| Sep 6 | 75°F | 41°F | 93°F 2022 | 29°F 1948 | 18% | 0% |
| Sep 7 | 74°F | 41°F | 91°F 2022 | 30°F 1962 | 18% | 0% |
| Sep 8 | 74°F | 41°F | 92°F 1979 | 25°F 1962 | 18% | 0% |
| Sep 9 | 74°F | 41°F | 92°F 2021 | 23°F 1962 | 18% | 0% |
| Sep 10 | 73°F | 41°F | 88°F 1959 | 29°F 1983 | 18% | 0% |
| Sep 11 | 73°F | 41°F | 90°F 1990 | 26°F 1989 | 18% | 0% |
| Sep 12 | 72°F | 40°F | 91°F 1953 | 22°F 1989 | 18% | 0% |
| Sep 13 | 72°F | 40°F | 90°F 1948 | 22°F 1974 | 18% | 0% |
| Sep 14 | 72°F | 40°F | 91°F 1948 | 22°F 1947 | 18% | 0% |
| Sep 15 | 71°F | 40°F | 92°F 2000 | 24°F 1965 | 18% | 0% |
| Sep 16 | 71°F | 39°F | 87°F 1979 | 20°F 1965 | 19% | 0% |
| Sep 17 | 71°F | 39°F | 85°F 1943 | 14°F 1965 | 19% | 0% |
| Sep 18 | 70°F | 39°F | 89°F 1981 | 17°F 1965 | 19% | 0% |
| Sep 19 | 70°F | 39°F | 88°F 1956 | 16°F 1983 | 19% | 0% |
| Sep 20 | 69°F | 39°F | 84°F 1991 | 10°F 1983 | 19% | 1% |
| Sep 21 | 69°F | 38°F | 86°F 1967 | 24°F 1983 | 19% | 1% |
| Sep 22 | 68°F | 38°F | 86°F 1987 | 24°F 1961 | 19% | 1% |
| Sep 23 | 68°F | 38°F | 88°F 1987 | 22°F 2000 | 19% | 1% |
| Sep 24 | 67°F | 37°F | 87°F 2001 | 18°F 2000 | 19% | 1% |
| Sep 25 | 67°F | 37°F | 87°F 2001 | 20°F 1984 | 19% | 1% |
| Sep 26 | 67°F | 37°F | 87°F 1952 | 21°F 1972 | 19% | 1% |
| Sep 27 | 66°F | 37°F | 84°F 1963 | 22°F 1961 | 19% | 1% |
| Sep 28 | 66°F | 36°F | 86°F 2010 | 21°F 1985 | 19% | 1% |
| Sep 29 | 65°F | 36°F | 86°F 1963 | 11°F 1985 | 19% | 1% |
| Sep 30 | 65°F | 36°F | 85°F 1963 | 15°F 1950 | 19% | 1% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (MDT).
- September 1
- sunrise 6:53 AM, sunset 8:08 PM
- September 30
- sunrise 7:28 AM, sunset 7:12 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00242409 (Dillon U Of Montana Western), public domain. Records: NOAA GHCN-Daily, station USW00024138, 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.