Gilroy weather in January

In January, Gilroy sees average daytime highs of 58°F and overnight lows near 41°F, with 3.4 in of rain across 8.3 wet days and about 9.7 hours of daylight. It is the 11th-warmest and 1st-wettest month of the year here.

Day-to-day highs hold fairly steady near 58°F through the month. The sky is clear or mostly clear about 36% of the time in January, and the air most often feels dry.

Daylight stretches from about 9 h 30 min at the start of January to 10 h 06 min by month's end. Set against the rest of the year, January is Gilroy's 12th-clearest and 9th-windiest month. For the whole year in context, see Gilroy's year-round climate.

Daytime high
58°
11th warmest
Overnight low
41°
2nd coldest
Rainfall
3.4 in
8.3 wet days
Daylight
9 h 42 min
7:24 AM – 5:07 PM
Cloud cover
55%
12th clearest
Wind
3 mph
9th windiest
Solar energy
2.6 kWh/m²
Travel score
4.6
out of 10

Gilroy is city in Santa Clara County, California, United States.

Density
1,272/km²
people per km²
Founded
1870

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in January

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 58°F through the month.

A typical January day in Gilroy reaches about 58°F in the afternoon and slips back to 41°F overnight — a 17°F spread between the day's warmth and the night's chill. On most days the high lands between 52°F and 65°F. Set against its neighbours, January runs on par with December and about 2°F cooler than February.

30°40°50°60°70°151015202531
Avg high (°F)Avg low (°F)
15740
25740
35740
45740
55740
65740
75741
85841
95841
105841
115841
125841
135841
145841
155841
165841
175841
185841
195841
205841
215841
225841
235942
245942
255942
265942
275942
285942
295942
306042
316042

Gilroy weather by month

How January compares with the rest of the year at a glance. January is the 11th-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan58° / 41°3.48.39.74.6
Feb60° / 43°3.48.510.65.0
Mar63° / 45°2.5811.76.0
Apr66° / 47°1.14.612.97.1
May70° / 50°0.52.8148.1
Jun75° / 53°0.10.614.59.2
Jul79° / 57°0.00.214.39.2
Aug79° / 57°0.00.113.49.2
Sep78° / 56°0.10.412.39.2
Oct73° / 51°0.71.9118.7
Nov64° / 45°1.44.7106.7
Dec58° / 40°3.07.79.54.6

Cloud cover in January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 36% of the time in January, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 13% of January, with mostly cloudy or overcast conditions the remaining 51%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14753
24753
34654
44753
54753
64753
74753
84852
94753
104753
114852
124852
134951
144951
154852
165050
175050
185050
195050
204951
215050
224951
234951
245050
254951
265050
275050
284951
295050
305050
315050

Chance of precipitation in January

Any precipitation

Gilroy gets around 3.4 in of rain over 8.3 wet days in January, the wettest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 27% and peaks near 29% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
127
227
327
427
527
626
726
826
926
1026
1126
1226
1327
1427
1527
1628
1728
1828
1929
2029
2129
2228
2328
2428
2527
2627
2727
2826
2926
3026
3126

Humidity in January

DryComfortableHumidMuggyOppressiveMiserable

Most of January feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, January lands in the dry band about 100% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
1991
2991
3991
4991
5991
6991
7991
8991
91000
101000
111000
121000
131000
141000
151000
161000
171000
181000
191000
201000
211000
221000
231000
241000
251000
261000
271000
28991
29991
30991
31991

Wind in January

Winds average 3 mph in January.

Across January, daily wind ranges from about 3 mph on the calmest days to 4 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
14calm
24calm
34calm
44calm
54calm
63calm
73calm
83calm
93calm
103calm
113calm
123calm
133calm
143calm
153calm
163calm
173calm
183calm
193calm
203calm
213calm
223calm
233calm
243calm
253calm
263calm
273calm
283calm
293calm
303calm
313calm

Sunrise & sunset in January

DaylightNight

Daylight runs from about 9 h 30 min at the start of January to 10 h 06 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 36 minutes over January. Sunrise moves from 7:24 AM to 7:17 AM, and sunset from 4:54 PM to 5:23 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.57:244:54
29.57:254:55
39.57:254:56
49.57:254:57
59.57:254:57
69.67:254:58
79.67:254:59
89.67:255:00
99.67:255:01
109.67:255:02
119.67:255:03
129.67:255:03
139.77:255:04
149.77:245:05
159.77:245:06
169.77:245:07
179.77:245:08
189.87:235:09
199.87:235:10
209.87:235:11
219.87:225:12
229.97:225:13
239.97:215:14
249.97:215:15
259.97:205:16
2610.07:205:17
2710.07:195:18
2810.07:195:19
2910.07:185:20
3010.17:175:21
3110.17:175:23

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 2.6 kWh/m².

For context, solar energy here swings from a low near 2.4 kWh/m² to a high of 7.96 kWh/m² in June across the year — January's 2.6 kWh/m² sits near the bottom.

01234151015202531
Solar energy (kWh/m²)Level
12.5Moderate
22.5Moderate
32.5Moderate
42.5Moderate
52.5Moderate
62.5Moderate
72.5Moderate
82.5Moderate
92.5Moderate
102.5Moderate
112.5Moderate
122.5Moderate
132.5Moderate
142.6Moderate
152.6Moderate
162.6Moderate
172.6Moderate
182.6Moderate
192.7Moderate
202.7Moderate
212.7Moderate
222.7Moderate
232.8Moderate
242.8Moderate
252.8Moderate
262.9Moderate
272.9Moderate
282.9Moderate
293.0Moderate
303.0Moderate
313.0Moderate
Planning a trip in January

Is January a good time to visit Gilroy?

Our two travel scores rate January for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

4.6
Sightseeing
11th-best month of the year
0.0
Beach & pool
12th-best month of the year

January is a reasonable time to visit Gilroy for sightseeing.

What to pack for Gilroy in January

From January's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In January, Gilroy sees daytime highs around 58°F and nights near 41°F. Worth packing: a warm layer and rain gear. About 8 days see rain.

a warm layerrain gear

Sea temperature near Gilroy in January

The nearest coast averages about 55°F in January — 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.

52°54°56°58°60°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°F)Comfort
Jan55Bracing
Feb55Bracing
Mar55Bracing
Apr54Bracing
May54Bracing
Jun55Bracing
Jul57Bracing
Aug58Bracing
Sep58Bracing
Oct58Bracing
Nov56Bracing
Dec55Bracing

UV index in Gilroy in January

LowModerateHighVery highExtreme

Clear-sky midday UV in January peaks 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.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJun 22UV 10Dec 14UV 2
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar4Moderate
Apr7High
May8Very high
Jun11Extreme
Jul10Extreme
Aug10Very high
Sep7High
Oct5High
Nov2Moderate
Dec2Moderate

Air quality in Gilroy in January

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where January 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).

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodAug 1920 µg/m³Jun 135 µg/m³
PM2.5 (µg/m³)Level
Jan7Good
Feb8Good
Mar8Good
Apr7Good
May6Good
Jun5Good
Jul8Good
Aug22Moderate
Sep15Moderate
Oct12Moderate
Nov8Good
Dec7Good
Location & terrain

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.

2 miles
640 ft
10 miles
2,871 ft
50 miles
5,161 ft
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
January weather nearby: Morgan Hill 9.9 mi · Watsonville 12 mi · Hollister 14 mi · Prunedale 17 mi · Live Oak 23 mi · Salinas 23 mi · Santa Cruz 25 mi · Marina 25 mi

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
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

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. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).