Snohomish County (Everett)
September
Weather in Snohomish County for September 2025
Your guide to Snohomish County weather in September - trends and predictions
In general, the average temperature in Snohomish County at the beginning of September is 24.6 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 15.4 °F by the end of September.
Snohomish County experiences moderate rainfall in September, with an average of 6 rainy days and a total precipitation of 49.4 mm.
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Temperatures
Rain 🌧️
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24
Dry days
6
Rainy days
0
Snow days
19°/11°
Temperatures
9 km/h
Avg max wind
82 %
Avg humidity
Snohomish County Weather September
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| Sun. | Mon. | Tue. | Wed. | Thu. | Fri. | Sat. |
|---|---|---|---|---|---|---|
| 1  26° | 2  24° | 3  22° | 4 23° | 5  27° | 6 26° | |
| 7 24° | 8 27° | 9 22° | 10 21° | 11  12° | 12 18° | 13 20° |
| 14 18° | 15 17° | 16 20° | 17 14° | 18 14° | 19 14° | 20 15° |
| 21 18° | 22  18° | 23 19° | 24 21° | 25  16° | 26  15° | 27 16° |
| 28 13° | 29 13° | 30  14° |
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Temperatures trend during September in Snohomish County
See the weather trend as well as the moving average line
September weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 | Partly cloudy | 26° /14° | 0 mm | 7 | |
| Sept. 2 | Fog | 24° /12° | 0 mm | 5 | |
| Sept. 3 | Patchy rain possible | 22° /12° | 0 mm | 5 | |
| Sept. 4 | Fog | 23° /11° | 0 mm | 5 | |
| Sept. 5 | Sunny | 27° /14° | 0 mm | 7 | |
| Sept. 6 | Sunny | 26° /14° | 0 mm | 7 | |
| Sept. 7 | Partly cloudy | 24° /14° | 0 mm | 6 | |
| Sept. 8 | Sunny | 27° /13° | 0 mm | 7 | |
| Sept. 9 | Fog | 22° /11° | 0 mm | 5 | |
| Sept. 10 | Patchy rain possible | 21° /10° | 0.1 mm | 5 | |
| Sept. 11 | Light rain | 12° /9° | 4 mm | 3 | |
| Sept. 12 | Fog | 18° /9° | 0.1 mm | 4 | |
| Sept. 13 | Mist | 20° /10° | 1.2 mm | 5 | |
| Sept. 14 | Light rain shower | 18° /12° | 4.8 mm | 4 | |
| Sept. 15 | Fog | 17° /10° | 0.1 mm | 4 | |
| Sept. 16 | Mist | 20° /8° | 0 mm | 5 | |
| Sept. 17 | Fog | 14° /10° | 0 mm | 3 | |
| Sept. 18 | Fog | 14° /12° | 0 mm | 3 | |
| Sept. 19 | Mist | 14° /10° | 0 mm | 3 | |
| Sept. 20 | Mist | 15° /9° | 0 mm | 4 | |
| Sept. 21 | Mist | 18° /7° | 0 mm | 4 | |
| Sept. 22 | Overcast | 18° /11° | 0 mm | 4 | |
| Sept. 23 | Mist | 19° /15° | 0 mm | 4 | |
| Sept. 24 | Mist | 21° /12° | 0 mm | 5 | |
| Sept. 25 | Moderate or heavy rain with thunder | 16° /12° | 20.8 mm | 4 | |
| Sept. 26 | Moderate rain at times | 15° /10° | 14 mm | 4 | |
| Sept. 27 | Mist | 16° /11° | 4.2 mm | 4 | |
| Sept. 28 | Mist | 13° /9° | 0 mm | 3 | |
| Sept. 29 | Mist | 13° /5° | 0 mm | 3 | |
| Sept. 30 | Cloudy | 14° /6° | 0 mm | 3 | |
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Important Notice
Our weather forecast for Snohomish County in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Snohomish County forecast closer to your planned date for the most up-to-date weather information.
Snohomish County in September - FAQ
What are the expected maximum and minimum temperatures in Snohomish County during September?
Enjoy moderate daytime temperatures of up to 19° and cooler nights around 11°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Snohomish County during September?
In September, Snohomish County can expect light to moderate rainfall, totaling 49.4 mm across approximately 6 days. Occasional showers are possible, and planning ahead for them could be helpful.
What are the typical wind conditions in Snohomish County during September?
The average wind speed in Snohomish County during September is 9 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Snohomish County
Explore the daily rainfall trends and prepare for Snohomish Countys September weather 💧
UV exposure in Snohomish County during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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Where is Snohomish County?Get accurate weather forecasts for Snohomish County, located at latitude 47.979 and longitude -122.202. Stay updated with localized weather information tailored for Snohomish County.
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