Washington Weather in September
Average highs run from 97°F on September 1 to 87°F on September 30, and lows from 66°F to 55°F. Normal precipitation for the month is 0.67 in over about 2 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
- 92°F
- Average low
- 61°F
- Precipitation
- 0.67 in
- Record high
- 112°FSep 7, 2022
- Record low
- 25°FSep 21, 1895
- Chance of a freeze
- 0%
- Days of 90°F or more
- 22.8
- Daylight
- 12 h 57 min to 11 h 50 min
- Cloud cover
- 27%
- Humidity
- 29%
- Dew point
- 37°F
- Wind
- 7.6 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 | 97°F | 66°F | 109°F 1995 | 45°F 1901 | 9% | 0% |
| Sep 2 | 97°F | 66°F | 109°F 2022 | 46°F 1902 | 9% | 0% |
| Sep 3 | 97°F | 66°F | 110°F 2022 | 43°F 1898 | 9% | 0% |
| Sep 4 | 96°F | 65°F | 109°F 2022 | 42°F 1898 | 9% | 0% |
| Sep 5 | 96°F | 65°F | 110°F 2020 | 38°F 1912 | 9% | 0% |
| Sep 6 | 96°F | 65°F | 110°F 2020 | 39°F 1912 | 9% | 0% |
| Sep 7 | 96°F | 64°F | 112°F 2022 | 39°F 1911 | 9% | 0% |
| Sep 8 | 95°F | 64°F | 108°F 2021 | 38°F 1911 | 9% | 0% |
| Sep 9 | 95°F | 63°F | 107°F 2021 | 41°F 1901 | 9% | 0% |
| Sep 10 | 95°F | 63°F | 105°F 1968 | 38°F 1901 | 9% | 0% |
| Sep 11 | 94°F | 63°F | 106°F 1990 | 40°F 1916 | 8% | 0% |
| Sep 12 | 94°F | 62°F | 105°F 1971 | 36°F 1903 | 8% | 0% |
| Sep 13 | 94°F | 62°F | 105°F 1971 | 33°F 1894 | 8% | 0% |
| Sep 14 | 93°F | 62°F | 104°F 1971 | 34°F 1894 | 8% | 0% |
| Sep 15 | 93°F | 61°F | 103°F 1971 | 36°F 1903 | 8% | 0% |
| Sep 16 | 93°F | 61°F | 103°F 1928 | 33°F 1903 | 8% | 0% |
| Sep 17 | 92°F | 60°F | 104°F 1935 | 33°F 1903 | 8% | 0% |
| Sep 18 | 92°F | 60°F | 104°F 1962 | 34°F 1903 | 8% | 0% |
| Sep 19 | 91°F | 59°F | 103°F 2000 | 33°F 1900 | 8% | 0% |
| Sep 20 | 91°F | 59°F | 103°F 2000 | 33°F 1900 | 8% | 0% |
| Sep 21 | 91°F | 59°F | 103°F 2000 | 25°F 1895 | 8% | 0% |
| Sep 22 | 90°F | 58°F | 103°F 2000 | 31°F 1895 | 8% | 0% |
| Sep 23 | 90°F | 58°F | 101°F 1966 | 29°F 1895 | 8% | 0% |
| Sep 24 | 89°F | 57°F | 100°F 1928 | 31°F 1916 | 8% | 0% |
| Sep 25 | 89°F | 57°F | 103°F 1947 | 31°F 1901 | 8% | 0% |
| Sep 26 | 88°F | 56°F | 100°F 1969 | 33°F 1912 | 8% | 0% |
| Sep 27 | 88°F | 56°F | 102°F 1942 | 32°F 1896 | 8% | 0% |
| Sep 28 | 88°F | 55°F | 102°F 2024 | 31°F 1900 | 8% | 0% |
| Sep 29 | 87°F | 55°F | 104°F 2024 | 31°F 1900 | 8% | 0% |
| Sep 30 | 87°F | 55°F | 101°F 2024 | 32°F 1900 | 8% | 0% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (MDT).
- September 1
- sunrise 7:05 AM, sunset 8:02 PM
- September 30
- sunrise 7:29 AM, sunset 7:19 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00427516 (St George), public domain. Records: NOAA GHCN-Daily, station USC00427516, 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.