Weather in San Bernardino County, California for September 2026
Until now, September 2026 in San Bernardino County has been nearly identical to the historical average, with a temperature of 23.4 °F (showing only a slight deviation of 0.1 °F).
The forecast for the upcoming days in San Bernardino County predicts a temperature of 24.7 °F, which is slightly above the historical average.
In general, the average temperature in San Bernardino County at the beginning of September is 24.7 °F. As the month progressed, temperatures tended to slightly increase, reaching an average of 24.9 °F by the end of September.
San Bernardino County experiences moderate rainfall in September, with an average of 6 rainy days and a total precipitation of 58.2 mm.
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San Bernardino County Weather September
Temperatures trend during September in San Bernardino County
September weather in San Bernardino County day by day
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 26° /17° | 0 mm | 8 | |
| Sept. 2 | Sunny | 24° /15° | 10.7 mm | 8 | |
| Sept. 3 | Sunny | 24° /14° | 3.6 mm | 8 | |
| Sept. 4 | Sunny | 24° /15° | 5.9 mm | 8 | |
| Sept. 5 |  Partly cloudy | 26° /16° | 6.8 mm | 8 | |
| Sept. 6 |  Cloudy | 24° /17° | 9.4 mm | 5 | |
| Sept. 7 |  Patchy rain possible | 25° /16° | 0.7 mm | 5 | |
| Sept. 8 |  Patchy light drizzle | 25° /17° | 1.1 mm | 6 | |
| Sept. 9 | Patchy rain possible | 25° /15° | 3 mm | 7 | |
| Sept. 10 | Sunny | 24° /13° | 1.6 mm | 8 | |
| Sept. 11 | Sunny | 23° /12° | 0.1 mm | 8 | |
| Sept. 12 | Partly cloudy | 23° /13° | 0 mm | 8 | |
| Sept. 13 | Sunny | 23° /13° | 0 mm | 7 | |
| Sept. 14 | Sunny | 25° /14° | 0 mm | 8 | |
| Sept. 15 | Sunny | 23° /14° | 0 mm | 8 | |
| Sept. 16 | Sunny | 19° /11° | 0 mm | 6 | |
| Sept. 17 | Cloudy | 21° /10° | 0 mm | 6 | |
| Sept. 18 | Sunny | 21° /11° | 0 mm | 7 | |
| Sept. 19 | Sunny | 21° /10° | 0 mm | 7 | |
| Sept. 20 |  Thundery outbreaks possible | 21° /10° | 0 mm | 4 | |
| Sept. 21 | Sunny | 20° /11° | 0 mm | 8.7 | |
| Sept. 22 | Sunny | 22° /11° | 0 mm | 8.5 | |
| Sept. 23 | Sunny | 25° /14° | 0 mm | 8.4 | |
| Sept. 24 | Sunny | 25° /17° | 0.4 mm | 7.8 | |
| Sept. 25 |  Overcast | 25° /16° | 0 mm | 7.4 | |
| Sept. 26 | Overcast | 25° /16° | 0 mm | 6 | |
| Sept. 27 | Sunny | 23° /13° | 0 mm | 6 | |
| Sept. 28 | Sunny | 24° /13° | 0 mm | 6 | |
| Sept. 29 | Sunny | 26° /15° | 0 mm | 7 | |
| Sept. 30 | Sunny | 26° /15° | 0 mm | 7 | |
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San Bernardino County in September - FAQ
What are the expected maximum and minimum temperatures in San Bernardino County during September?
How much rainfall should be expected in San Bernardino County during September?
What are the typical wind conditions in San Bernardino County during September?
September rainfall patterns in San Bernardino County
UV exposure in San Bernardino County during September
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Where is San Bernardino County?Get accurate weather forecasts for San Bernardino County, located at latitude 34.244 and longitude -116.911. Stay updated with localized weather information tailored for San Bernardino County.