Lewis County Weather in September
Average highs run from 78°F on September 1 to 69°F on September 30, and lows from 50°F to 46°F. Normal precipitation for the month is 2.46 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
- 74°F
- Average low
- 48°F
- Precipitation
- 2.46 in
- Record high
- 100°FSep 2, 1988
- Record low
- 24°FSep 25, 1908
- Chance of a freeze
- 0%
- Days of 90°F or more
- 2.8
- Daylight
- 13 h 18 min to 11 h 44 min
- Cloud cover
- 51%
- Humidity
- 73%
- Dew point
- 47°F
- Wind
- 3.8 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 | 50°F | 92°F 1987 | 38°F 1914 | 26% | 0% |
| Sep 2 | 78°F | 50°F | 100°F 1988 | 34°F 1919 | 27% | 0% |
| Sep 3 | 78°F | 50°F | 98°F 1935 | 39°F 1932 | 27% | 0% |
| Sep 4 | 78°F | 50°F | 93°F 1909 | 33°F 1906 | 27% | 0% |
| Sep 5 | 77°F | 50°F | 100°F 1944 | 36°F 1905 | 28% | 0% |
| Sep 6 | 77°F | 50°F | 92°F 1949 | 33°F 1905 | 28% | 0% |
| Sep 7 | 77°F | 50°F | 96°F 1981 | 38°F 1913 | 29% | 0% |
| Sep 8 | 77°F | 49°F | 94°F 1935 | 37°F 1914 | 29% | 0% |
| Sep 9 | 77°F | 49°F | 94°F 1907 | 37°F 1945 | 30% | 0% |
| Sep 10 | 76°F | 49°F | 99°F 1944 | 36°F 1906 | 30% | 0% |
| Sep 11 | 76°F | 49°F | 91°F 2011 | 35°F 1936 | 31% | 0% |
| Sep 12 | 76°F | 49°F | 94°F 1924 | 30°F 1949 | 31% | 0% |
| Sep 13 | 76°F | 49°F | 92°F 1999 | 29°F 1921 | 32% | 0% |
| Sep 14 | 75°F | 48°F | 97°F 1938 | 30°F 1921 | 32% | 0% |
| Sep 15 | 75°F | 48°F | 93°F 1967 | 33°F 1921 | 33% | 0% |
| Sep 16 | 75°F | 48°F | 89°F 1951 | 32°F 1908 | 34% | 0% |
| Sep 17 | 74°F | 48°F | 96°F 1938 | 32°F 1902 | 34% | 0% |
| Sep 18 | 74°F | 48°F | 88°F 1991 | 33°F 1902 | 35% | 0% |
| Sep 19 | 74°F | 48°F | 90°F 1999 | 34°F 1957 | 35% | 0% |
| Sep 20 | 73°F | 47°F | 89°F 1974 | 35°F 1925 | 36% | 0% |
| Sep 21 | 73°F | 47°F | 92°F 1952 | 34°F 1902 | 36% | 0% |
| Sep 22 | 72°F | 47°F | 92°F 1990 | 33°F 1902 | 37% | 0% |
| Sep 23 | 72°F | 47°F | 91°F 1925 | 30°F 1908 | 37% | 0% |
| Sep 24 | 72°F | 47°F | 97°F 1943 | 27°F 1908 | 38% | 0% |
| Sep 25 | 71°F | 47°F | 90°F 1922 | 24°F 1908 | 38% | 0% |
| Sep 26 | 71°F | 46°F | 85°F 2000 | 28°F 1908 | 39% | 0% |
| Sep 27 | 70°F | 46°F | 91°F 1967 | 30°F 1972 | 39% | 0% |
| Sep 28 | 70°F | 46°F | 87°F 1932 | 34°F 1929 | 40% | 0% |
| Sep 29 | 69°F | 46°F | 88°F 1993 | 29°F 1919 | 41% | 0% |
| Sep 30 | 69°F | 46°F | 87°F 1987 | 30°F 1950 | 41% | 0% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (PDT).
- September 1
- sunrise 6:30 AM, sunset 7:48 PM
- September 30
- sunrise 7:07 AM, sunset 6:51 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00455110 (Mayfield Pwr Plt), public domain. Records: NOAA GHCN-Daily, station USC00451276, 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.