Weather in Clark County, Washington for September 2025
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Until now, September 2025 in Clark County is slightly cooler than the historical average by -0.7 °F.
Expect cooler weather in the next days in Clark County with the forecast suggesting a temperature of 22.9 °F, lower than the historical average.
In general, the average temperature in Clark County at the beginning of September is 27.7 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 18.6 °F by the end of September.
Clark County experiences moderate rainfall in September, with an average of 8 rainy days and a total precipitation of 47.3 mm.
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Clark County Weather September
Temperatures trend during September in Clark County
September weather in Clark County day by day
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Fog | 27° /14° | 0.1 mm | 6 | |
| Sept. 2 |  Cloudy | 28° /13° | 0.1 mm | 6 | |
| Sept. 3 |  Patchy rain possible | 27° /15° | 0.7 mm | 6 | |
| Sept. 4 |  Overcast | 27° /13° | 0.5 mm | 6 | |
| Sept. 5 |  Sunny | 32° /15° | 0 mm | 8 | |
| Sept. 6 |  Partly cloudy | 28° /15° | 0 mm | 7 | |
| Sept. 7 | Cloudy | 25° /15° | 0 mm | 6 | |
| Sept. 8 | Overcast | 26° /13° | 3.2 mm | 6 | |
| Sept. 9 | Mist | 26° /13° | 4.4 mm | 6 | |
| Sept. 10 | Sunny | 24° /13° | 0 mm | 6 | |
| Sept. 11 | Overcast | 20° /12° | 3.5 mm | 4 | |
| Sept. 12 | Cloudy | 21° /11° | 0.2 mm | 5 | |
| Sept. 13 | Mist | 24° /10° | 0 mm | 6 | |
| Sept. 14 | Sunny | 25° /11° | 1.4 mm | 6 | |
| Sept. 15 | Sunny | 25° /11° | 0 mm | 1.4 | |
| Sept. 16 | Sunny | 33° /18° | 0 mm | 1.4 | |
| Sept. 17 | Sunny | 27° /16° | 0 mm | 1.4 | |
| Sept. 18 | Partly cloudy | 27° /14° | 0 mm | 1.2 | |
| Sept. 19 | Partly cloudy | 25° /13° | 0 mm | 0 | |
| Sept. 20 | Patchy rain possible | 15° /10° | 0.4 mm | 3 | |
| Sept. 21 | Partly cloudy | 24° /14° | 0 mm | 5 | |
| Sept. 22 | Sunny | 25° /14° | 0 mm | 5 | |
| Sept. 23 | Sunny | 29° /12° | 0 mm | 5 | |
| Sept. 24 | Patchy rain possible | 20° /12° | 2 mm | 4 | |
| Sept. 25 | Patchy rain possible | 19° /10° | 0.8 mm | 3 | |
| Sept. 26 | Patchy rain possible | 14° /9° | 0.3 mm | 3 | |
| Sept. 27 | Partly cloudy | 23° /9° | 0 mm | 5 | |
| Sept. 28 |  Moderate rain | 14° /11° | 5.1 mm | 3 | |
| Sept. 29 | Overcast | 19° /8° | 0 mm | 4 | |
| Sept. 30 | Sunny | 21° /7° | 0 mm | 6 | |
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Clark County in September - FAQ
September rainfall patterns in Clark County
UV exposure in Clark County during September
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Where is Clark County?Get accurate weather forecasts for Clark County, located at latitude 45.639 and longitude -122.661. Stay updated with localized weather information tailored for Clark County.