Click on a day for an hourly weather forecast
The weather in San Diego in September is hot. The average temperatures are between 20°C and 27°C.
You can expect a few rainy days in San Diego during September, but usually the weather is comfortable in September.
Our weather forecast can give you a great sense of what weather to expect in San Diego in September 2025.
If you’re planning to visit San Diego in the near future, we highly recommend that you review the 14 day weather forecast for San Diego before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 19° / 11° | 2 | 29 | 0 | 56 mm | Good | San Diego in January |
| February | 19° / 11° | 2 | 26 | 0 | 66 mm | Good | San Diego in February |
| March | 19° / 12° | 2 | 29 | 0 | 44 mm | Good | San Diego in March |
| April | 20° / 13° | 1 | 29 | 0 | 16 mm | Good | San Diego in April |
| May | 21° / 14° | 1 | 30 | 0 | 19 mm | Good | San Diego in May |
| June | 23° / 17° | 0 | 30 | 0 | 5 mm | Perfect | San Diego in June |
| July | 26° / 20° | 1 | 30 | 0 | 25 mm | Perfect | San Diego in July |
| August | 27° / 21° | 1 | 30 | 0 | 21 mm | Perfect | San Diego in August |
| September | 27° / 20° | 1 | 29 | 0 | 15 mm | Perfect | San Diego in September |
| October | 25° / 18° | 1 | 30 | 0 | 10 mm | Perfect | San Diego in October |
| November | 22° / 15° | 1 | 29 | 0 | 34 mm | Good | San Diego in November |
| December | 18° / 11° | 2 | 29 | 0 | 60 mm | Good | San Diego in December |