Weather in Clark County, Washington for September 2026
Until now, September 2026 in Clark County is cooler than usual, with temperatures averaging 22 °F, this is 2.5 °F below the typical seasonal average.
The forecast for the coming days of September 2026 predicts a temperature of 24.6 °F , which is warmer than usual.
In general, the average temperature in Clark County at the beginning of September is 26.1 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 20.7 °F by the end of September.
The climate of Clark County in September is notably wet, with an average of 13 rainy days, and a total of 60.3 mm of precipitation.
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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 |  Overcast | 27° /14° | 0.1 mm | 5 | |
| Sept. 2 |  Cloudy | 25° /13° | 11.7 mm | 5 | |
| Sept. 3 |  Patchy rain possible | 24° /14° | 9.1 mm | 5 | |
| Sept. 4 | Overcast | 26° /12° | 4 mm | 5 | |
| Sept. 5 |  Sunny | 30° /14° | 0 mm | 7 | |
| Sept. 6 |  Partly cloudy | 26° /14° | 5.1 mm | 5 | |
| Sept. 7 | Patchy rain possible | 25° /14° | 1.5 mm | 5 | |
| Sept. 8 | Sunny | 27° /12° | 2.4 mm | 6 | |
| Sept. 9 |  Mist | 27° /13° | 3.3 mm | 6 | |
| Sept. 10 | Sunny | 24° /13° | 0 mm | 6 | |
| Sept. 11 | Overcast | 20° /11° | 2.6 mm | 4 | |
| Sept. 12 | Overcast | 21° /11° | 1.8 mm | 4 | |
| Sept. 13 | Mist | 23° /10° | 0.4 mm | 5 | |
| Sept. 14 | Patchy rain possible | 24° /11° | 1.1 mm | 6 | |
| Sept. 15 | Sunny | 25° /10° | 0.2 mm | 5 | |
| Sept. 16 | Sunny | 29° /12° | 0 mm | 7 | |
| Sept. 17 | Sunny | 24° /13° | 5.1 mm | 6 | |
| Sept. 18 | Overcast | 22° /12° | 0 mm | 5 | |
| Sept. 19 | Overcast | 24° /12° | 0 mm | 6 | |
| Sept. 20 | Light rain shower | 23° /11° | 0.3 mm | 5 | |
| Sept. 21 | Partly cloudy | 23° /10° | 4.1 mm | 5 | |
| Sept. 22 | Sunny | 23° /11° | 0 mm | 5 | |
| Sept. 23 | Overcast | 25° /13° | 0.8 mm | 5 | |
| Sept. 24 | Sunny | 26° /13° | 2.8 mm | 5 | |
| Sept. 25 |  Heavy rain at times | 19° /12° | 7.2 mm | 4 | |
| Sept. 26 | Light rain shower | 20° /10° | 2.8 mm | 4 | |
| Sept. 27 | Sunny | 21° /7° | 0 mm | 3.7 | |
| Sept. 28 | Sunny | 22° /6° | 0 mm | 4.2 | |
| Sept. 29 | Overcast | 17° /9° | 0.1 mm | 4.1 | |
| Sept. 30 | Overcast | 20° /7° | 0 mm | 4 | |
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Clark County in September - FAQ
What are the expected maximum and minimum temperatures in Clark County during September?
How much rainfall should be expected in Clark County during September?
What are the typical wind conditions in Clark County during September?
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.