Riverside County (Riverside)
September
Weather in Riverside County, California for September 2025
Your guide to Riverside County weather in September - trends and predictions
Until now, September 2025 in Riverside County is slightly cooler than the historical average by -0.6 °F.
Expect cooler weather in the next days in Riverside County with the forecast suggesting a temperature of 31.9 °F, lower than the historical average.
In general, the average temperature in Riverside County at the beginning of September is 34.6 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 30 °F by the end of September.
With an average of 2 rainy days, Riverside County experiences minimal rainfall in September.
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Temperatures
Rain 🌧️
More
28
Dry days
2
Rainy days
0
Snow days
30°/19°
Temperatures
17 km/h
Avg max wind
48 %
Avg humidity
Riverside County Weather September
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Temperatures trend during September in Riverside County
See the weather trend as well as the moving average line
September weather in Riverside County day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 35° /21° | 0.3 mm | 8 | |
| Sept. 2 |  Overcast | 34° /23° | 0 mm | 8 | |
| Sept. 3 |  Light rain | 32° /21° | 0.7 mm | 7 | |
| Sept. 4 | Sunny | 34° /21° | 0 mm | 8 | |
| Sept. 5 | Sunny | 35° /22° | 0 mm | 8 | |
| Sept. 6 | Sunny | 36° /22° | 0 mm | 9 | |
| Sept. 7 | Sunny | 36° /22° | 0 mm | 8 | |
| Sept. 8 | Sunny | 36° /23° | 0.1 mm | 8 | |
| Sept. 9 | Sunny | 35° /22° | 0 mm | 8 | |
| Sept. 10 |  Cloudy | 31° /21° | 0 mm | 7 | |
| Sept. 11 | Cloudy | 30° /20° | 0 mm | 7 | |
| Sept. 12 | Sunny | 29° /17° | 0 mm | 7 | |
| Sept. 13 | Sunny | 29° /16° | 0 mm | 7 | |
| Sept. 14 | Sunny | 31° /17° | 0 mm | 8 | |
| Sept. 15 | Sunny | 31° /17° | 0 mm | 8 | |
| Sept. 16 | Sunny | 38° /22° | 0 mm | 1.9 | |
| Sept. 17 |  Partly cloudy | 35° /21° | 0 mm | 1.6 | |
| Sept. 18 | Overcast | 31° /20° | 0 mm | 1.8 | |
| Sept. 19 |  Patchy rain possible | 28° /22° | 1.1 mm | 1 | |
| Sept. 20 | Sunny | 30° /20° | 0 mm | 0 | |
| Sept. 21 | Sunny | 33° /22° | 0 mm | 7 | |
| Sept. 22 | Sunny | 35° /23° | 0 mm | 7 | |
| Sept. 23 | Sunny | 34° /26° | 0 mm | 7 | |
| Sept. 24 | Sunny | 32° /24° | 0 mm | 7 | |
| Sept. 25 | Sunny | 33° /23° | 0 mm | 7 | |
| Sept. 26 | Sunny | 31° /21° | 0 mm | 6 | |
| Sept. 27 | Sunny | 28° /18° | 0 mm | 6 | |
| Sept. 28 | Sunny | 28° /20° | 0 mm | 6 | |
| Sept. 29 | Sunny | 30° /18° | 0 mm | 6 | |
| Sept. 30 | Light rain shower | 28° /16° | 1 mm | 7 | |
| Next | |||||
Important Notice
Our weather forecast for Riverside 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 Riverside County forecast closer to your planned date for the most up-to-date weather information.
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Riverside County in September - FAQ
What are the expected maximum and minimum temperatures in Riverside County during September?
Expect warm days with temperatures around 30°, cooling to mild conditions of 19° after sunset. Perfect for those who enjoy warm weather.
How much rainfall should be expected in Riverside County during September?
Rainfall in Riverside County during September is rare to nonexistent, with the total expected rainfall being less than 10 mm and approximately 2 days seeing any precipitation. Planning without the concern for rain is generally straightforward during this very dry period.
What are the typical wind conditions in Riverside County during September?
The average wind speed in Riverside County during September is 17 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Riverside County
Explore the daily rainfall trends and prepare for Riverside Countys September weather 💧
UV exposure in Riverside County during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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Where is Riverside County?Get accurate weather forecasts for Riverside County, located at latitude 33.953 and longitude -117.396. Stay updated with localized weather information tailored for Riverside County.
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