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Gilroy Weather by Month
Average temperatures, rainfall and humidity for Gilroy, United States, month by month, built from OpenWeather’s historical records. Use it to see what a typical Gilroy month looks like before you travel — then check the live Gilroy forecast for the days ahead.
Warmest month
September
24°C average high
Coolest month
December
7°C average low
Wettest month
December
76 mm of rain
Driest month
July
1 mm of rain
Average temperature and rainfall in Gilroy by month
Averages of the daily highs and lows recorded in each month, with total rainfall, mean humidity and mean wind speed.
| Month | Avg high | Avg low | Record low / high | Rainfall | Humidity | Wind |
|---|---|---|---|---|---|---|
| January | 16°C | 7°C | -2°C / 27°C | 52 mm | 75% | 11 km/h |
| February | 17°C | 7°C | -3°C / 29°C | 56 mm | 74% | 12 km/h |
| March | 18°C | 8°C | 2°C / 33°C | 49 mm | 75% | 12 km/h |
| April | 19°C | 9°C | 3°C / 33°C | 28 mm | 73% | 13 km/h |
| May | 19°C | 10°C | 5°C / 33°C | 18 mm | 74% | 14 km/h |
| June | 22°C | 12°C | 7°C / 37°C | 4 mm | 74% | 12 km/h |
| July | 23°C | 13°C | 8°C / 37°C | 1 mm | 76% | 13 km/h |
| August | 24°C | 14°C | 10°C / 37°C | 2 mm | 76% | 12 km/h |
| September | 24°C | 13°C | 7°C / 41°C | 4 mm | 74% | 11 km/h |
| October | 23°C | 11°C | 5°C / 38°C | 23 mm | 71% | 10 km/h |
| November | 19°C | 8°C | 0°C / 33°C | 34 mm | 71% | 10 km/h |
| December | 16°C | 7°C | -5°C / 26°C | 76 mm | 76% | 11 km/h |
Best time to visit Gilroy
The most comfortable time to visit Gilroy is generally July to September, balancing mild daytime temperatures against the driest stretch of the year. The city has a moderate seasonal swing and rain concentrates around December, totalling about 348 mm a year.
Travellers who prefer heat should aim for September, when highs average 24°C. December is the month to avoid if rain would spoil your plans — it averages 76 mm, roughly 53× the rainfall of the driest month (July).
Source: OpenWeather historical and statistical weather data. Values are long-term averages, not a forecast — see the Gilroy forecast for what is happening now.