Tri-Cities
September
Weather in Tri-Cities for September 2025
Your guide to Tri-Cities weather in September - trends and predictions
In general, the average temperature in Tri-Cities at the beginning of September is 32.9 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 23.6 °F by the end of September.
With an average of 4 rainy days, Tri-Cities experiences minimal rainfall in September.
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Temperatures
Rain 🌧️
More
26
Dry days
4
Rainy days
0
Snow days
28°/13°
Temperatures
19 km/h
Avg max wind
43 %
Avg humidity
Tri-Cities in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  33° | 2  34° | 3  31° | 4 31° | 5  33° | 6 34° | 7 34° |
| 8 34° | 9 33° | 10  33° | 11 27° | 12 28° | 13 27° | 14 28° |
| 15 29° | 16 31° | 17 26° | 18 28° | 19 27° | 20 21° | 21 20° |
| 22 25° | 23 26° | 24 27° | 25 26° | 26 25° | 27 23° | 28 23° |
| 29 20° | 30 21° |
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Temperatures trend during September in Tri-Cities
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 | Light rain | 33° /16° | 3.7 mm | 8 | |
| Sept. 2 | Patchy rain possible | 34° /16° | 0.3 mm | 8 | |
| Sept. 3 | Overcast | 31° /17° | 0.2 mm | 8 | |
| Sept. 4 | Overcast | 31° /14° | 0 mm | 7 | |
| Sept. 5 | Sunny | 33° /15° | 0 mm | 8 | |
| Sept. 6 | Sunny | 34° /16° | 0 mm | 8 | |
| Sept. 7 | Sunny | 34° /16° | 0 mm | 8 | |
| Sept. 8 | Sunny | 34° /18° | 0 mm | 9 | |
| Sept. 9 | Sunny | 33° /16° | 0 mm | 8 | |
| Sept. 10 | Partly cloudy | 33° /15° | 0 mm | 8 | |
| Sept. 11 | Overcast | 27° /16° | 0 mm | 6 | |
| Sept. 12 | Overcast | 28° /13° | 0 mm | 6 | |
| Sept. 13 | Sunny | 27° /12° | 0 mm | 7 | |
| Sept. 14 | Sunny | 28° /12° | 0 mm | 8 | |
| Sept. 15 | Sunny | 29° /13° | 0 mm | 7 | |
| Sept. 16 | Sunny | 31° /14° | 0 mm | 8 | |
| Sept. 17 | Overcast | 26° /13° | 0 mm | 6 | |
| Sept. 18 | Overcast | 28° /12° | 0 mm | 7 | |
| Sept. 19 | Overcast | 27° /10° | 0 mm | 7 | |
| Sept. 20 | Light rain shower | 21° /10° | 0.7 mm | 5 | |
| Sept. 21 | Light rain | 20° /8° | 1.7 mm | 5 | |
| Sept. 22 | Overcast | 25° /7° | 0 mm | 6 | |
| Sept. 23 | Overcast | 26° /10° | 0 mm | 6 | |
| Sept. 24 | Overcast | 27° /14° | 0 mm | 7 | |
| Sept. 25 | Overcast | 26° /13° | 0 mm | 6 | |
| Sept. 26 | Light rain shower | 25° /11° | 0.6 mm | 6 | |
| Sept. 27 | Light rain | 23° /10° | 1 mm | 6 | |
| Sept. 28 | Overcast | 23° /8° | 0 mm | 6 | |
| Sept. 29 | Light drizzle | 20° /9° | 0.4 mm | 5 | |
| Sept. 30 | Patchy rain possible | 21° /5° | 1.7 mm | 5 | |
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Important Notice
Our weather forecast for Tri-Cities 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 Tri-Cities forecast closer to your planned date for the most up-to-date weather information.
Tri-Cities in September - FAQ
What are the expected maximum and minimum temperatures in Tri-Cities during September?
Enjoy moderate daytime temperatures of up to 28° and cooler nights around 13°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Tri-Cities during September?
Expect minimal rainfall in Tri-Cities during September, with a total of 10.4 mm over approximately 4 days. This minimal precipitation is unlikely to significantly impact plans.
What are the typical wind conditions in Tri-Cities during September?
The average wind speed in Tri-Cities during September is 19 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Tri-Cities
Explore the daily rainfall trends and prepare for Tri-Citiess September weather 💧
UV exposure in Tri-Cities during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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Where is Tri-Cities?Get accurate weather forecasts for Tri-Cities, located at latitude 46.245 and longitude -119.196. Stay updated with localized weather information tailored for Tri-Cities.
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