San Bernardino (CA)
September
Weather in San Bernardino, California for September 2026
Your guide to San Bernardino weather in September - trends and predictions
So far, September 2026 in San Bernardino is slightly warmer than the historical average by 1.1 °F.
The forecast for the upcoming days in San Bernardino predicts a temperature of 32.1 °F, which is slightly above the historical average.
In general, the average temperature in San Bernardino at the beginning of September is 35 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 31.6 °F by the end of September.
With an average of 3 rainy days, San Bernardino 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°/18°
Temperatures
15 km/h
Avg max wind
47 %
Avg humidity
San Bernardino Weather September
Move between months or click on a day
Temperatures trend during September in San Bernardino
See the weather trend as well as the moving average line
September weather in San Bernardino day by day
Click on a date for more information
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 36° /20° | 0.3 mm | 9 | |
| Sept. 2 | Sunny | 35° /20° | 1.4 mm | 9 | |
| Sept. 3 | Sunny | 33° /18° | 1.4 mm | 8 | |
| Sept. 4 | Sunny | 34° /18° | 0 mm | 9 | |
| Sept. 5 | Sunny | 36° /19° | 0 mm | 9 | |
| Sept. 6 | Sunny | 35° /21° | 3.6 mm | 8 | |
| Sept. 7 | Sunny | 36° /21° | 0 mm | 7 | |
| Sept. 8 | Sunny | 38° /22° | 0 mm | 9 | |
| Sept. 9 | Sunny | 37° /21° | 0.2 mm | 9 | |
| Sept. 10 |  Cloudy | 34° /21° | 0 mm | 8 | |
| Sept. 11 |  Partly cloudy | 32° /19° | 0 mm | 8 | |
| Sept. 12 | Sunny | 31° /17° | 0 mm | 8 | |
| Sept. 13 | Sunny | 30° /16° | 0 mm | 8 | |
| Sept. 14 | Sunny | 31° /16° | 0 mm | 8 | |
| Sept. 15 | Sunny | 31° /17° | 0 mm | 8 | |
| Sept. 16 | Sunny | 30° /17° | 0 mm | 8 | |
| Sept. 17 |  Overcast | 27° /15° | 0.3 mm | 7 | |
| Sept. 18 | Cloudy | 27° /16° | 0 mm | 7 | |
| Sept. 19 | Sunny | 27° /15° | 0 mm | 7 | |
| Sept. 20 | Partly cloudy | 27° /15° | 0 mm | 6 | |
| Sept. 21 | Sunny | 25° /16° | 0 mm | 8 | |
| Sept. 22 | Sunny | 28° /15° | 0 mm | 7.8 | |
| Sept. 23 | Sunny | 34° /22° | 0 mm | 7.8 | |
| Sept. 24 | Sunny | 32° /23° | 0.1 mm | 7.6 | |
| Sept. 25 | Sunny | 32° /23° | 0 mm | 6.8 | |
| Sept. 26 | Overcast | 32° /24° | 0 mm | 8 | |
| Sept. 27 | Sunny | 31° /23° | 0 mm | 8 | |
| Sept. 28 | Sunny | 30° /20° | 0 mm | 8 | |
| Sept. 29 | Sunny | 32° /22° | 0 mm | 8 | |
| Sept. 30 | Sunny | 32° /21° | 0 mm | 8 | |
| Next | |||||
Important Notice
Our weather forecast for San Bernardino 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 forecast closer to your planned date for the most up-to-date weather information.
Change Month
San Bernardino in September - FAQ
What are the expected maximum and minimum temperatures in San Bernardino during September?
Expect warm days with temperatures around 31°, cooling to mild conditions of 18° after sunset. Perfect for those who enjoy warm weather.
How much rainfall should be expected in San Bernardino during September?
Rainfall in San Bernardino 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 during September?
The average wind speed in San Bernardino during September is 15 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in San Bernardino
Explore the daily rainfall trends and prepare for San Bernardinos September weather 💧
Typically, San Bernardino has 3 rainy days in September with a total of 5.4 mm of rainfall.
UV exposure in San Bernardino during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
Quick links
More San Bernardino weather pages
You are here
Where is San Bernardino?Get accurate weather forecasts for San Bernardino, located at latitude 34.108 and longitude -117.29. Stay updated with localized weather information tailored for San Bernardino.
Found a mistake?
We appreciate your attention to details. Tell us here.