Click on a day for an hourly weather forecast
The temperatures in San Bernardino in September are comfortable with low of 14°C and and high up to 32°C.
There is little to no rain in San Bernardino during September, so it’s a lot easier to explore the city. Just remember to dress in warm layers, as it can still get pretty chilly.
Our weather forecast can give you a great sense of what weather to expect in San Bernardino in September 2025.
If you’re planning to visit San Bernardino in the near future, we highly recommend that you review the 14 day weather forecast for San Bernardino before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 18° / 5° | 2 | 29 | 0 | 50 mm | Good | San Bernardino in January |
| February | 18° / 5° | 2 | 26 | 0 | 55 mm | Good | San Bernardino in February |
| March | 20° / 5° | 2 | 29 | 0 | 31 mm | Good | San Bernardino in March |
| April | 23° / 7° | 1 | 29 | 0 | 23 mm | Perfect | San Bernardino in April |
| May | 26° / 9° | 0 | 31 | 0 | 7 mm | Perfect | San Bernardino in May |
| June | 31° / 12° | 0 | 30 | 0 | 2 mm | Good | San Bernardino in June |
| July | 34° / 15° | 1 | 30 | 0 | 18 mm | Ok | San Bernardino in July |
| August | 34° / 16° | 0 | 31 | 0 | 10 mm | Ok | San Bernardino in August |
| September | 32° / 14° | 0 | 30 | 0 | 7 mm | Good | San Bernardino in September |
| October | 27° / 10° | 0 | 31 | 0 | 8 mm | Perfect | San Bernardino in October |
| November | 22° / 7° | 1 | 29 | 0 | 18 mm | Good | San Bernardino in November |
| December | 17° / 4° | 3 | 28 | 0 | 63 mm | Good | San Bernardino in December |