Gilroy in Winter
In winter (December, January and February), Gilroy sees average daytime highs around 59°F and overnight lows near 41°F, with 9.8 in of rain over about 25 wet days across the season. It is the coldest season of the year and the wettest season of the year.
Across winter, daytime highs hold fairly steady around 59°F. The sky is clear or mostly clear about 36% of the time across winter, and the air most often feels dry.
Winter is Gilroy's weakest season of the year to visit on our travel score. For the whole year in context, see Gilroy's year-round climate.
- Avg daytime high
- 59°F
- coldest season of the year
- Avg overnight low
- 41°F
- Rainfall
- 9.8 in
- 25 wet days
- Avg wind
- 4 mph
- Travel score
- 4.7
- weakest season of the year
- Months
- Dec · Jan · Feb
Temperature in Gilroy in Winter
Across winter, daytime highs hold fairly steady around 59°F.
A typical winter day in Gilroy reaches about 59°F and drops to 41°F overnight. The warmest of the three months is February, the coolest December.
Gilroy weather by month
How the three winter months (December, January and February) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 58° / 41° | 3.4 | 8.3 | 9.7 | 4.6 |
| Feb | 60° / 43° | 3.4 | 8.5 | 10.6 | 5.0 |
| Mar | 63° / 45° | 2.5 | 8 | 11.7 | 6.0 |
| Apr | 66° / 47° | 1.1 | 4.6 | 12.9 | 7.1 |
| May | 70° / 50° | 0.5 | 2.8 | 14 | 8.1 |
| Jun | 75° / 53° | 0.1 | 0.6 | 14.5 | 9.2 |
| Jul | 79° / 57° | 0.0 | 0.2 | 14.3 | 9.2 |
| Aug | 79° / 57° | 0.0 | 0.1 | 13.4 | 9.2 |
| Sep | 78° / 56° | 0.1 | 0.4 | 12.3 | 9.2 |
| Oct | 73° / 51° | 0.7 | 1.9 | 11 | 8.7 |
| Nov | 64° / 45° | 1.4 | 4.7 | 10 | 6.7 |
| Dec | 58° / 40° | 3.0 | 7.7 | 9.5 | 4.6 |
Cloud cover in Winter
The sky is clear or mostly clear about 36% of the time across winter.
Chance of precipitation in Winter
Gilroy gets around 9.8 in of rain over 25 wet days across winter. The line is the day-by-day chance of measurable precipitation.
Humidity in Winter
Most of winter feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Winter
Winds average 4 mph across winter.
Sunrise & sunset in Winter
Daylight runs from about 9 h 36 min in early December to 11 h 06 min by late February. The lit band spans sunrise to sunset each day.
Solar energy in Winter
Average shortwave solar energy reaching the ground each day across winter, about 2.8 kWh/m².
Is winter a good time to visit Gilroy?
Our two travel scores rate winter for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
winter is a reasonable time to visit Gilroy for sightseeing.
What to pack for Gilroy in Winter
From winter's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In winter, Gilroy sees daytime highs around 59°F and nights near 41°F. Worth packing: a warm layer and rain gear. About 25 days see rain.
Sea temperature near Gilroy in Winter
The nearest coast averages about 55°F across winter — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 19 mi away) is warmest in September at about 58°F and coldest in April near 54°F.
The water stays below 68°F all year — cool enough that most swimmers want a wetsuit.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°F) | 55 | 55 | 55 | 54 | 54 | 55 | 57 | 58 | 58 | 58 | 56 | 55 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing |
| Sea temperature (°F) | Comfort | |
|---|---|---|
| Jan | 55 | Bracing |
| Feb | 55 | Bracing |
| Mar | 55 | Bracing |
| Apr | 54 | Bracing |
| May | 54 | Bracing |
| Jun | 55 | Bracing |
| Jul | 57 | Bracing |
| Aug | 58 | Bracing |
| Sep | 58 | Bracing |
| Oct | 58 | Bracing |
| Nov | 56 | Bracing |
| Dec | 55 | Bracing |
UV index in Gilroy in Winter
Clear-sky midday UV across winter averages around 3. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Gilroy peaks around June 22 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 14 at about 2 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 3 | 4 | 4 | 7 | 8 | 11 | 10 | 10 | 7 | 5 | 2 | 2 |
| Level | Moderate | Moderate | Moderate | High | Very high | Extreme | Extreme | Very high | High | High | Moderate | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 3 | Moderate |
| Feb | 4 | Moderate |
| Mar | 4 | Moderate |
| Apr | 7 | High |
| May | 8 | Very high |
| Jun | 11 | Extreme |
| Jul | 10 | Extreme |
| Aug | 10 | Very high |
| Sep | 7 | High |
| Oct | 5 | High |
| Nov | 2 | Moderate |
| Dec | 2 | Moderate |
Air quality in Gilroy in Winter
Average fine-particle pollution (PM2.5) through the year — so you can see where winter falls, not just the annual average.
Air quality in Gilroy is worst in August — around 22 µg/m³ PM2.5 (moderate), about 4.2× the cleanest month (June, 5 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 7 | 8 | 8 | 7 | 6 | 5 | 8 | 22 | 15 | 12 | 8 | 7 |
| Level | Good | Good | Good | Good | Good | Good | Good | Moderate | Moderate | Moderate | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 7 | Good |
| Feb | 8 | Good |
| Mar | 8 | Good |
| Apr | 7 | Good |
| May | 6 | Good |
| Jun | 5 | Good |
| Jul | 8 | Good |
| Aug | 22 | Moderate |
| Sep | 15 | Moderate |
| Oct | 12 | Moderate |
| Nov | 8 | Good |
| Dec | 7 | Good |
Where is Gilroy?
Gilroy sits at 37.0°N, 121.6°W, 200 ft above sea level, in United States. The nearest listed city is Morgan Hill, 9.9 mi away.
Topography around Gilroy
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Gilroy.
Within 2 miles, the terrain around Gilroy has only modest variations in elevation — a maximum elevation change of 640 ft around an average of 217 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,871 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 5,161 ft.
The land around Gilroy is covered by artificial surfaces (49%) and cropland (25%) within 2 miles, trees (38%) and grassland (36%) within 10 miles, and grassland (39%) and trees (27%) within 50 miles.
United States travel facts
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 100% of US
- price level, 2025
- GDP per capita
- $90,027
- 2025
- Happiness
- 6.8 / 10
- World Happiness, 2025
- Safe drinking water
- 98%
- of population, 2024
- Homicide rate
- 5.8
- per 100k, 2023
- Road deaths
- 12.7
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Gilroy (37.0058°, -121.5683°, elevation 200 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.