Mandan Weather in September
Average highs run from 78°F on September 1 to 65°F on September 30, and lows from 51°F to 40°F. Normal precipitation for the month is 1.64 in over about 6 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
- 72°F
- Average low
- 46°F
- Precipitation
- 1.64 in
- Record high
- 104°FSep 7, 1931
- Record low
- 14°FSep 30, 1974
- Chance of a freeze
- 63%
- Days of 90°F or more
- 1.5
- Daylight
- 13 h 20 min to 11 h 44 min
- Cloud cover
- 54%
- Humidity
- 59%
- Dew point
- 43°F
- Wind
- 11.2 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 | 78°F | 51°F | 103°F 1929 | 33°F 1974 | 21% | 0% |
| Sep 2 | 77°F | 51°F | 100°F 1983 | 33°F 1946 | 21% | 0% |
| Sep 3 | 77°F | 51°F | 101°F 1971 | 30°F 1974 | 21% | 0% |
| Sep 4 | 77°F | 50°F | 100°F 1931 | 35°F 1962 | 21% | 0% |
| Sep 5 | 76°F | 50°F | 102°F 1913 | 29°F 1965 | 21% | 0% |
| Sep 6 | 76°F | 50°F | 103°F 1978 | 31°F 1956 | 21% | 0% |
| Sep 7 | 76°F | 49°F | 104°F 1931 | 34°F 1929 | 21% | 0% |
| Sep 8 | 75°F | 49°F | 96°F 1931 | 29°F 2020 | 21% | 0% |
| Sep 9 | 75°F | 49°F | 104°F 1959 | 25°F 2020 | 21% | 0% |
| Sep 10 | 75°F | 48°F | 98°F 1994 | 28°F 1943 | 21% | 0% |
| Sep 11 | 74°F | 48°F | 101°F 1952 | 24°F 1964 | 21% | 0% |
| Sep 12 | 74°F | 47°F | 96°F 1948 | 27°F 1989 | 21% | |
| Sep 13 | 73°F | 47°F | 93°F 1927 | 25°F 1970 | 21% | |
| Sep 14 | 73°F | 47°F | 94°F 2015 | 25°F 1949 | 21% | |
| Sep 15 | 73°F | 46°F | 98°F 1935 | 23°F 1916 | 21% | |
| Sep 16 | 72°F | 46°F | 103°F 1948 | 28°F 1973 | 21% | |
| Sep 17 | 72°F | 45°F | 95°F 1979 | 28°F 1993 | 20% | |
| Sep 18 | 71°F | 45°F | 97°F 1933 | 25°F 1929 | 20% | |
| Sep 19 | 71°F | 45°F | 94°F 1941 | 23°F 1991 | 20% | |
| Sep 20 | 70°F | 44°F | 93°F 1972 | 22°F 1918 | 20% | |
| Sep 21 | 70°F | 44°F | 94°F 1960 | 25°F 1934 | 20% | |
| Sep 22 | 70°F | 43°F | 94°F 1936 | 19°F 1995 | 20% | |
| Sep 23 | 69°F | 43°F | 90°F 1917 | 22°F 1989 | 20% | |
| Sep 24 | 69°F | 42°F | 93°F 1958 | 24°F 1985 | 20% | |
| Sep 25 | 68°F | 42°F | 91°F 1938 | 16°F 1926 | 19% | |
| Sep 26 | 68°F | 42°F | 90°F 2014 | 16°F 1942 | 19% | |
| Sep 27 | 67°F | 41°F | 95°F 1963 | 18°F 1942 | 19% | |
| Sep 28 | 67°F | 41°F | 96°F 1952 | 20°F 1951 | 19% | |
| Sep 29 | 66°F | 40°F | 88°F 1931 | 22°F 1945 | 19% | |
| Sep 30 | 65°F | 40°F | 96°F 2024 | 14°F 1974 | 19% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (CDT).
- September 1
- sunrise 7:03 AM, sunset 8:23 PM
- September 30
- sunrise 7:41 AM, sunset 7:25 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00325479 (Mandan Exp Stn), public domain. Records: NOAA GHCN-Daily, station USC00325479, 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.