Tri-Cities (WA)
September
Weather in Tri-Cities, Washington for September 2027
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 32.1 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 23.9 °C by the end of September.
With an average of 3 rainy days, Tri-Cities experiences minimal rainfall in September.
Is September a good time to visit Tri-Cities? check out the best time to travel to Tri-Cities page.
✨ Is September a good time to visit Tri-Cities? – Ask the AI Weatherman
Temperatures
Rain 🌧️
More
27
Dry days
3
Rainy days
0
Snow days
28°/13°
Temperatures
19 km/h
Avg max wind
44 %
Avg humidity
Tri-Cities Weather September
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Temperatures trend during September in Tri-Cities
See the weather trend as well as the moving average line
September weather in Tri-Cities day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Light rain | 34° /17° | 1.9 mm | 6 | |
| Sept. 2 |  Patchy rain possible | 34° /16° | 0.2 mm | 6 | |
| Sept. 3 |  Overcast | 31° /17° | 0.2 mm | 6.7 | |
| Sept. 4 |  Sunny | 31° /14° | 0 mm | 6.6 | |
| Sept. 5 | Sunny | 32° /16° | 0.3 mm | 6.5 | |
| Sept. 6 | Light rain | 31° /16° | 2.6 mm | 6 | |
| Sept. 7 | Sunny | 32° /17° | 0.2 mm | 6.4 | |
| Sept. 8 | Sunny | 32° /15° | 0 mm | 6.3 | |
| Sept. 9 | Sunny | 30° /15° | 0 mm | 6.2 | |
| Sept. 10 | Overcast | 32° /15° | 0 mm | 6 | |
| Sept. 11 | Patchy rain possible | 26° /16° | 2 mm | 5 | |
| Sept. 12 | Patchy rain possible | 27° /13° | 1.4 mm | 5 | |
| Sept. 13 | Sunny | 26° /13° | 0.9 mm | 5.8 | |
| Sept. 14 | Patchy rain possible | 25° /13° | 1.2 mm | 5.7 | |
| Sept. 15 | Sunny | 26° /12° | 0 mm | 5.6 | |
| Sept. 16 | Sunny | 29° /14° | 0 mm | 5.5 | |
| Sept. 17 | Overcast | 27° /14° | 0.1 mm | 5.4 | |
| Sept. 18 | Overcast | 28° /14° | 0 mm | 5.3 | |
| Sept. 19 | Overcast | 29° /12° | 0 mm | 5.3 | |
| Sept. 20 | Sunny | 25° /13° | 0.4 mm | 5.2 | |
| Sept. 21 | Overcast | 23° /12° | 0.8 mm | 5 | |
| Sept. 22 | Overcast | 25° /10° | 0 mm | 5 | |
| Sept. 23 | Overcast | 26° /11° | 0 mm | 4.9 | |
| Sept. 24 | Overcast | 27° /14° | 0 mm | 4.8 | |
| Sept. 25 | Overcast | 25° /13° | 0.7 mm | 4.7 | |
| Sept. 26 | Light rain shower | 24° /11° | 0.3 mm | 4.6 | |
| Sept. 27 | Light rain | 23° /10° | 0.5 mm | 4.5 | |
| Sept. 28 | Overcast | 24° /10° | 0 mm | 4.4 | |
| Sept. 29 | Overcast | 22° /12° | 0.2 mm | 4 | |
| Sept. 30 | Overcast | 22° /10° | 0.9 mm | 4 | |
| Next | |||||
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.
Change Month
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 14.8 mm over approximately 3 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 💧
Typically, Tri-Cities has 3 rainy days in September with a total of 14.8 mm of rainfall.
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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