Fairfax Weather in September
Average highs run from 82°F on September 1 to 72°F on September 30, and lows from 59°F to 47°F.
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
- 78°F
- Average low
- 54°F
- Record high
- 111°FSep 1, 1922
- Record low
- 21°FSep 25, 1928
- Chance of a freeze
- 9%
- Days of 90°F or more
- 2.5
- Daylight
- 13 h 04 min to 11 h 48 min
- Cloud cover
- 46%
- Humidity
- 67%
- Dew point
- 54°F
- Wind
- 10.1 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 | 82°F | 59°F | 111°F 1922 | 42°F 1949 | 0% | |
| Sep 2 | 82°F | 59°F | 107°F 2000 | 45°F 1924 | 0% | |
| Sep 3 | 82°F | 59°F | 111°F 1947 | 42°F 1974 | 0% | |
| Sep 4 | 82°F | 58°F | 106°F 1913 | 41°F 1974 | 0% | |
| Sep 5 | 81°F | 58°F | 107°F 1913 | 43°F 1962 | 0% | |
| Sep 6 | 81°F | 58°F | 105°F 1939 | 37°F 1988 | 0% | |
| Sep 7 | 81°F | 57°F | 106°F 1922 | 43°F 1956 | 0% | |
| Sep 8 | 81°F | 57°F | 103°F 1922 | 39°F 1986 | 0% | |
| Sep 9 | 80°F | 57°F | 100°F 1919 | 38°F 2008 | 0% | |
| Sep 10 | 80°F | 56°F | 102°F 1938 | 40°F 1995 | 0% | |
| Sep 11 | 80°F | 56°F | 101°F 1936 | 39°F 1940 | 0% | |
| Sep 12 | 79°F | 55°F | 98°F 1939 | 34°F 1945 | 0% | |
| Sep 13 | 79°F | 55°F | 104°F 1931 | 35°F 2014 | 0% | |
| Sep 14 | 79°F | 55°F | 102°F 1939 | 40°F 1974 | 0% | |
| Sep 15 | 78°F | 54°F | 101°F 1939 | 31°F 1993 | 0% | |
| Sep 16 | 78°F | 54°F | 100°F 1931 | 35°F 1993 | 0% | |
| Sep 17 | 78°F | 53°F | 98°F 1953 | 39°F 1943 | 0% | |
| Sep 18 | 77°F | 53°F | 98°F 1948 | 37°F 1973 | 0% | |
| Sep 19 | 77°F | 52°F | 101°F 1931 | 28°F 1991 | 0% | |
| Sep 20 | 76°F | 52°F | 100°F 2022 | 30°F 1991 | 0% | |
| Sep 21 | 76°F | 51°F | 98°F 1956 | 32°F 1918 | 0% | |
| Sep 22 | 76°F | 51°F | 95°F 1921 | 25°F 1995 | 0% | |
| Sep 23 | 75°F | 50°F | 94°F 1921 | 28°F 1983 | 0% | |
| Sep 24 | 75°F | 50°F | 91°F 1999 | 28°F 1989 | 0% | |
| Sep 25 | 74°F | 50°F | 94°F 1998 | 21°F 1928 | 0% | |
| Sep 26 | 74°F | 49°F | 96°F 1938 | 28°F 1926 | 0% | |
| Sep 27 | 74°F | 49°F | 95°F 1990 | 29°F 1942 | 0% | |
| Sep 28 | 73°F | 48°F | 103°F 1953 | 28°F 1942 | 0% | |
| Sep 29 | 73°F | 48°F | 98°F 1953 | 25°F 1984 | 0% | |
| Sep 30 | 72°F | 47°F | 93°F 2023 | 28°F 1984 | 0% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (CDT).
- September 1
- sunrise 6:49 AM, sunset 7:53 PM
- September 30
- sunrise 7:17 AM, sunset 7:05 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USW00014945 (Tarkio), public domain. Records: NOAA GHCN-Daily, station USW00094957, 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.