Click on a day for an hourly weather forecast
The temperatures in Gilroy in September are comfortable with low of 14°C and and high up to 28°C.
There is little to no rain in Gilroy 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 Gilroy in September 2025.
If you’re planning to visit Gilroy in the near future, we highly recommend that you review the 14 day weather forecast for Gilroy before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 16° / 5° | 5 | 26 | 0 | 95 mm | Good | Gilroy in January |
| February | 17° / 5° | 5 | 24 | 0 | 72 mm | Good | Gilroy in February |
| March | 18° / 6° | 6 | 25 | 0 | 89 mm | Good | Gilroy in March |
| April | 20° / 7° | 3 | 27 | 0 | 30 mm | Good | Gilroy in April |
| May | 23° / 9° | 1 | 30 | 0 | 11 mm | Perfect | Gilroy in May |
| June | 26° / 11° | 0 | 30 | 0 | 3 mm | Perfect | Gilroy in June |
| July | 28° / 13° | 0 | 31 | 0 | 2 mm | Perfect | Gilroy in July |
| August | 28° / 13° | 0 | 31 | 0 | 0 mm | Perfect | Gilroy in August |
| September | 28° / 14° | 0 | 30 | 0 | 4 mm | Perfect | Gilroy in September |
| October | 25° / 11° | 1 | 30 | 0 | 24 mm | Perfect | Gilroy in October |
| November | 19° / 7° | 4 | 27 | 0 | 43 mm | Good | Gilroy in November |
| December | 15° / 5° | 6 | 25 | 0 | 94 mm | Good | Gilroy in December |