Washington Weather in September
Average highs run from 73°F on September 1 to 62°F on September 30, and lows from 55°F to 46°F. Normal precipitation for the month is 3.22 in over about 10 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
- 68°F
- Average low
- 51°F
- Precipitation
- 3.22 in
- Record high
- 94°FSep 1, 1953
- Record low
- 26°FSep 28, 1976
- Chance of a freeze
- 15%
- Daylight
- 13 h 16 min to 11 h 45 min
- Cloud cover
- 63%
- Humidity
- 80%
- Dew point
- 54°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 | 73°F | 55°F | 94°F 1953 | 40°F 1970 | 31% | 0% |
| Sep 2 | 73°F | 55°F | 90°F 1953 | 32°F 1976 | 31% | 0% |
| Sep 3 | 72°F | 55°F | 87°F 1983 | 35°F 1946 | 32% | 0% |
| Sep 4 | 72°F | 55°F | 85°F 1948 | 39°F 1997 | 32% | 0% |
| Sep 5 | 72°F | 54°F | 85°F 1998 | 37°F 1984 | 32% | 0% |
| Sep 6 | 71°F | 54°F | 86°F 2007 | 37°F 1949 | 32% | 0% |
| Sep 7 | 71°F | 54°F | 85°F 1976 | 36°F 1986 | 32% | 0% |
| Sep 8 | 71°F | 53°F | 84°F 2015 | 36°F 1956 | 32% | 0% |
| Sep 9 | 70°F | 53°F | 83°F 1983 | 33°F 1975 | 32% | 0% |
| Sep 10 | 70°F | 53°F | 85°F 1961 | 34°F 1995 | 33% | 0% |
| Sep 11 | 70°F | 53°F | 85°F 1952 | 36°F 1958 | 33% | 0% |
| Sep 12 | 69°F | 52°F | 82°F 1969 | 35°F 1955 | 33% | 0% |
| Sep 13 | 69°F | 52°F | 82°F 1952 | 36°F 1963 | 33% | 0% |
| Sep 14 | 69°F | 52°F | 80°F 2005 | 32°F 1975 | 33% | 0% |
| Sep 15 | 68°F | 51°F | 81°F 2009 | 36°F 1988 | 34% | 0% |
| Sep 16 | 68°F | 51°F | 79°F 1994 | 31°F 1945 | 34% | 0% |
| Sep 17 | 67°F | 51°F | 82°F 1948 | 32°F 1959 | 34% | 0% |
| Sep 18 | 67°F | 50°F | 80°F 2018 | 32°F 1959 | 34% | 0% |
| Sep 19 | 67°F | 50°F | 79°F 1967 | 33°F 1979 | 34% | 0% |
| Sep 20 | 66°F | 49°F | 77°F 1998 | 34°F 1973 | 34% | 0% |
| Sep 21 | 66°F | 49°F | 78°F 1970 | 31°F 1956 | 34% | 0% |
| Sep 22 | 65°F | 49°F | 78°F 1970 | 33°F 1982 | 35% | 0% |
| Sep 23 | 65°F | 48°F | 77°F 1984 | 29°F 1974 | 35% | 0% |
| Sep 24 | 64°F | 48°F | 78°F 2017 | 27°F 1976 | 35% | 0% |
| Sep 25 | 64°F | 48°F | 77°F 2007 | 35°F 1947 | 35% | 0% |
| Sep 26 | 64°F | 47°F | 76°F 2017 | 28°F 1976 | 35% | 0% |
| Sep 27 | 63°F | 47°F | 75°F 1998 | 29°F 1957 | 36% | 0% |
| Sep 28 | 63°F | 46°F | 75°F 1987 | 26°F 1976 | 36% | 0% |
| Sep 29 | 62°F | 46°F | 76°F 2024 | 28°F 1949 | 36% | 0% |
| Sep 30 | 62°F | 46°F | 77°F 2024 | 28°F 1945 | 36% | 0% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (CDT).
- September 1
- sunrise 6:09 AM, sunset 7:25 PM
- September 30
- sunrise 6:45 AM, sunset 6:30 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00478905 (Washington Is), public domain. Records: NOAA GHCN-Daily, station USC00478905, 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.