San Bernardino County (San Bernardino)
September
Weather in San Bernardino County for September 2025
Your guide to San Bernardino County weather in September - trends and predictions
In general, the average temperature in San Bernardino County at the beginning of September is 34.6 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 31.4 °F by the end of September.
With an average of 3 rainy days, San Bernardino County experiences minimal rainfall in September.
New! Chat with our AI weatherman - it’s amazing and free.
Temperatures
Rain 🌧️
More
27
Dry days
3
Rainy days
0
Snow days
31°/17°
Temperatures
15 km/h
Avg max wind
45 %
Avg humidity
San Bernardino County in September average weather
Move between months or click on a day
| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  34° | 2  34° | 3 32° | 4  33° | 5 35° | 6 37° | 7  37° |
| 8 37° | 9 38° | 10  36° | 11 33° | 12 31° | 13 30° | 14 30° |
| 15 29° | 16 27° | 17 24° | 18 24° | 19 24° | 20 23° | 21 23° |
| 22  29° | 23 33° | 24 32° | 25 32° | 26 32° | 27 32° | 28 32° |
| 29 32° | 30 28° |
You can click on date
Access San Bernardino County weather forecasts with a simple click. Select any date for comprehensive insights on temperature, rainfall, and wind conditions.
Temperatures trend during September in San Bernardino County
See the weather trend as well as the moving average line
September weather day by day
Click on a date for more information
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 | Patchy rain possible | 34° /20° | 0.6 mm | 8 | |
| Sept. 2 | Light rain | 34° /19° | 1.1 mm | 8 | |
| Sept. 3 | Light rain | 32° /16° | 2.7 mm | 8 | |
| Sept. 4 | Partly cloudy | 33° /17° | 0 mm | 8 | |
| Sept. 5 | Partly cloudy | 35° /20° | 0 mm | 9 | |
| Sept. 6 | Partly cloudy | 37° /20° | 0 mm | 9 | |
| Sept. 7 | Sunny | 37° /22° | 0.1 mm | 8 | |
| Sept. 8 | Partly cloudy | 37° /24° | 0 mm | 9 | |
| Sept. 9 | Sunny | 38° /24° | 0 mm | 9 | |
| Sept. 10 | Cloudy | 36° /23° | 0 mm | 8 | |
| Sept. 11 | Partly cloudy | 33° /21° | 0 mm | 8 | |
| Sept. 12 | Sunny | 31° /16° | 0 mm | 8 | |
| Sept. 13 | Sunny | 30° /14° | 0 mm | 8 | |
| Sept. 14 | Sunny | 30° /15° | 0 mm | 8 | |
| Sept. 15 | Partly cloudy | 29° /15° | 0 mm | 8 | |
| Sept. 16 | Sunny | 27° /14° | 0.1 mm | 7 | |
| Sept. 17 | Partly cloudy | 24° /11° | 0 mm | 6 | |
| Sept. 18 | Cloudy | 24° /13° | 0 mm | 6 | |
| Sept. 19 | Partly cloudy | 24° /12° | 0 mm | 6 | |
| Sept. 20 | Partly cloudy | 23° /12° | 0 mm | 6 | |
| Sept. 21 | Patchy rain possible | 23° /12° | 0 mm | 6 | |
| Sept. 22 | Overcast | 29° /12° | 0 mm | 7 | |
| Sept. 23 | Cloudy | 33° /16° | 0 mm | 8 | |
| Sept. 24 | Sunny | 32° /16° | 0 mm | 8 | |
| Sept. 25 | Sunny | 32° /16° | 0 mm | 8 | |
| Sept. 26 | Overcast | 32° /15° | 0 mm | 8 | |
| Sept. 27 | Partly cloudy | 32° /17° | 0 mm | 8 | |
| Sept. 28 | Sunny | 32° /16° | 0 mm | 8 | |
| Sept. 29 | Sunny | 32° /16° | 0 mm | 8 | |
| Sept. 30 | Light rain shower | 28° /15° | 1.7 mm | 7 | |
| Next | |||||
Important Notice
Our weather forecast for San Bernardino 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 San Bernardino County forecast closer to your planned date for the most up-to-date weather information.
San Bernardino County in September - FAQ
What are the expected maximum and minimum temperatures in San Bernardino County during September?
Expect warm days with temperatures around 31°, cooling to mild conditions of 17° after sunset. Perfect for those who enjoy warm weather.
How much rainfall should be expected in San Bernardino County during September?
Rainfall in San Bernardino County during September is rare to nonexistent, with the total expected rainfall being less than 10 mm and approximately 3 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 San Bernardino County during September?
The average wind speed in San Bernardino County during September is 15 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in San Bernardino County
Explore the daily rainfall trends and prepare for San Bernardino Countys September weather 💧
UV exposure in San Bernardino County during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
Top locations in San Bernardino County
Select a location for an accurate weather forecast
More Locations Quick links
You are here
Where is San Bernardino County?Get accurate weather forecasts for San Bernardino County, located at latitude 34.108 and longitude -117.29. Stay updated with localized weather information tailored for San Bernardino County.
Found a mistake?
We appreciate your attention to details. Tell us here.