Click on a day for an hourly weather forecast
The temperatures in San Jose in September are comfortable with low of 17°C and and high up to 22°C.
With more than 22 rainy days, San Jose is an incredibly wet during September. Be sure to pack your umbrella and bring along your rubber boots to stay dry. It’s going to be raining cats and dogs this month!
Our weather forecast can give you a great sense of what weather to expect in San Jose in September 2025.
If you’re planning to visit San Jose in the near future, we highly recommend that you review the 14 day weather forecast for San Jose before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 23° / 14° | 4 | 27 | 0 | 92 mm | Perfect | San Jose in January |
| February | 24° / 14° | 4 | 25 | 0 | 78 mm | Perfect | San Jose in February |
| March | 25° / 15° | 5 | 26 | 0 | 92 mm | Perfect | San Jose in March |
| April | 25° / 16° | 13 | 17 | 0 | 231 mm | Good | San Jose in April |
| May | 23° / 17° | 24 | 7 | 0 | 749 mm | Good | San Jose in May |
| June | 22° / 17° | 26 | 4 | 0 | 855 mm | Ok | San Jose in June |
| July | 22° / 17° | 24 | 7 | 0 | 685 mm | Ok | San Jose in July |
| August | 22° / 17° | 25 | 6 | 0 | 757 mm | Ok | San Jose in August |
| September | 22° / 17° | 28 | 2 | 0 | 793 mm | Awful | San Jose in September |
| October | 22° / 17° | 27 | 4 | 0 | 943 mm | Awful | San Jose in October |
| November | 22° / 16° | 19 | 11 | 0 | 481 mm | Ok | San Jose in November |
| December | 23° / 15° | 9 | 22 | 0 | 186 mm | Good | San Jose in December |