| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 16.4° | 4.5° | 107.3mm | 9.7 | 69 |
| February | 18° | 5.3° | 95.2mm | 9.1 | 75 |
| March | 20.4° | 6.6° | 59.8mm | 7.7 | 85 |
| April | 22.7° | 7.8° | 32.8mm | 5.5 | 89 |
| May | 25.6° | 10.1° | 11.9mm | 2.3 | 95 |
| June | 29° | 11.9° | 1.5mm | 0.5 | 91 |
| July | 30.8° | 13.4° | 0mm | 0.1 | 85 |
| August | 30.9° | 13.2° | 0.9mm | 0.2 | 84 |
| September | 30° | 12.6° | 1.6mm | 0.6 | 87 |
| October | 26° | 9.5° | 26.6mm | 2.6 | 95 |
| November | 20.4° | 6.6° | 43.6mm | 6 | 88 |
| December | 16.1° | 4.1° | 118.6mm | 9.5 | 69 |
January in Gilroy averages a daily high of 16.4°C with nights around 4.5°C. Expect roughly 9.7 wet days totalling 107.3mm. Generally workable, with some weather to plan around.
February in Gilroy averages a daily high of 18°C with nights around 5.3°C. Expect roughly 9.1 wet days totalling 95.2mm. Comfortable conditions for being outdoors all day.
March in Gilroy averages a daily high of 20.4°C with nights around 6.6°C. Expect roughly 7.7 wet days totalling 59.8mm. Comfortable conditions for being outdoors all day.
April in Gilroy averages a daily high of 22.7°C with nights around 7.8°C. Expect roughly 5.5 wet days totalling 32.8mm. Comfortable conditions for being outdoors all day.
May in Gilroy averages a daily high of 25.6°C with nights around 10.1°C. Rain is rare — about 2.3 wet days and 11.9mm across the month. Comfortable conditions for being outdoors all day.
June in Gilroy averages a daily high of 29°C with nights around 11.9°C. Rain is rare — about 0.5 wet days and 1.5mm across the month. Comfortable conditions for being outdoors all day.
July in Gilroy averages a daily high of 30.8°C with nights around 13.4°C. Rain is rare — about 0.1 wet days and 0mm across the month. Comfortable conditions for being outdoors all day.
August in Gilroy averages a daily high of 30.9°C with nights around 13.2°C. Rain is rare — about 0.2 wet days and 0.9mm across the month. Comfortable conditions for being outdoors all day.
September in Gilroy averages a daily high of 30°C with nights around 12.6°C. Rain is rare — about 0.6 wet days and 1.6mm across the month. Comfortable conditions for being outdoors all day.
October in Gilroy averages a daily high of 26°C with nights around 9.5°C. Rain is rare — about 2.6 wet days and 26.6mm across the month. Comfortable conditions for being outdoors all day.
November in Gilroy averages a daily high of 20.4°C with nights around 6.6°C. Expect roughly 6 wet days totalling 43.6mm. Comfortable conditions for being outdoors all day.
December in Gilroy averages a daily high of 16.1°C with nights around 4.1°C. Expect roughly 9.5 wet days totalling 118.6mm. Generally workable, with some weather to plan around.
Each month scores out of 100. It starts at 100 and loses points for daytime highs outside a 20–27°C band, for wet days, and for nights below 2°C. Nothing else is weighted in — no crowd data, no prices, no opinion. Gilroy peaks at 95.
Based on 30 years of records, April–June scores highest for comfort in Gilroy, balancing daytime temperature against rainfall.
August is the warmest, averaging a daily high of 30.9°C.
December is the wettest, averaging 118.6mm of rain across roughly 9.5 wet days.
December is the coolest month, with average daily highs around 16.1°C.