Mount Rainier Weather in September
Average highs run from 86°F on September 1 to 76°F on September 30, and lows from 66°F to 56°F. Normal precipitation for the month is 4.12 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
- 82°F
- Average low
- 62°F
- Precipitation
- 4.12 in
- Record high
- 101°FSep 1, 1953
- Record low
- 29°FSep 30, 1942
- Chance of a freeze
- 0%
- Days of 90°F or more
- 4.3
- Daylight
- 13 h 01 min to 11 h 49 min
- Cloud cover
- 55%
- Humidity
- 71%
- Dew point
- 58°F
- Wind
- 8.1 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 | 86°F | 66°F | 101°F 1953 | 43°F 1946 | 31% | 0% |
| Sep 2 | 86°F | 66°F | 98°F 1962 | 36°F 1949 | 31% | 0% |
| Sep 3 | 86°F | 66°F | 100°F 1953 | 45°F 1964 | 31% | 0% |
| Sep 4 | 86°F | 66°F | 98°F 1953 | 46°F 1946 | 31% | 0% |
| Sep 5 | 85°F | 65°F | 95°F 1985 | 45°F 1997 | 31% | 0% |
| Sep 6 | 85°F | 65°F | 97°F 1985 | 43°F 1976 | 31% | 0% |
| Sep 7 | 85°F | 65°F | 98°F 1954 | 43°F 1962 | 31% | 0% |
| Sep 8 | 85°F | 64°F | 98°F 1954 | 42°F 1962 | 31% | 0% |
| Sep 9 | 84°F | 64°F | 95°F 1946 | 40°F 1986 | 31% | 0% |
| Sep 10 | 84°F | 64°F | 95°F 1985 | 35°F 1956 | 31% | 0% |
| Sep 11 | 84°F | 63°F | 98°F 1983 | 39°F 1976 | 31% | 0% |
| Sep 12 | 83°F | 63°F | 98°F 1983 | 38°F 1967 | 31% | 0% |
| Sep 13 | 83°F | 63°F | 94°F 1998 | 36°F 1941 | 31% | 0% |
| Sep 14 | 83°F | 62°F | 92°F 1952 | 38°F 1941 | 31% | 0% |
| Sep 15 | 82°F | 62°F | 94°F 1952 | 38°F 1946 | 31% | 0% |
| Sep 16 | 82°F | 62°F | 93°F 1998 | 38°F 1946 | 31% | 0% |
| Sep 17 | 81°F | 61°F | 96°F 1991 | 40°F 1986 | 31% | 0% |
| Sep 18 | 81°F | 61°F | 96°F 1991 | 38°F 1986 | 31% | 0% |
| Sep 19 | 81°F | 60°F | 91°F 1978 | 36°F 1943 | 31% | 0% |
| Sep 20 | 80°F | 60°F | 92°F 1965 | 37°F 1959 | 31% | 0% |
| Sep 21 | 80°F | 60°F | 90°F 1997 | 30°F 1956 | 31% | 0% |
| Sep 22 | 79°F | 59°F | 92°F 1998 | 33°F 1962 | 31% | 0% |
| Sep 23 | 79°F | 59°F | 94°F 1970 | 37°F 1947 | 31% | 0% |
| Sep 24 | 79°F | 58°F | 94°F 1970 | 32°F 1963 | 31% | 0% |
| Sep 25 | 78°F | 58°F | 93°F 1970 | 31°F 1963 | 31% | 0% |
| Sep 26 | 78°F | 58°F | 93°F 1970 | 36°F 1943 | 31% | 0% |
| Sep 27 | 77°F | 57°F | 93°F 1986 | 34°F 1947 | 31% | 0% |
| Sep 28 | 77°F | 57°F | 95°F 1998 | 32°F 1947 | 31% | 0% |
| Sep 29 | 77°F | 56°F | 91°F 1945 | 33°F 1942 | 31% | 0% |
| Sep 30 | 76°F | 56°F | 93°F 1954 | 29°F 1942 | 31% | 0% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (EDT).
- September 1
- sunrise 6:37 AM, sunset 7:38 PM
- September 30
- sunrise 7:03 AM, sunset 6:52 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00186350 (Natl Arboretum Dc), public domain. Records: NOAA GHCN-Daily, station USC00180700, 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.