Hercules weather in January

In January, Hercules sees average daytime highs of 57°F and overnight lows near 42°F, with 4.0 in of rain across 9.3 wet days and about 9.7 hours of daylight. It is the 11th-warmest and 2nd-wettest month of the year here.

Highs climb over the month, from about 56°F in the first days to 59°F by the end. The sky is clear or mostly clear about 32% of the time in January, and the air most often feels dry.

Daylight stretches from about 9 h 24 min at the start of January to 10 hours by month's end. Set against the rest of the year, January is Hercules's 12th-clearest and 11th-windiest month. For the whole year in context, see Hercules's year-round climate.

Daytime high
57°
11th warmest
Overnight low
42°
2nd coldest
Rainfall
4.0 in
9.3 wet days
Daylight
9 h 36 min
7:29 AM – 5:07 PM
Cloud cover
61%
12th clearest
Wind
5 mph
11th windiest
Solar energy
2.29 kWh/m²
Travel score
4.2
out of 10

Hercules is city in western Contra Costa County, California, United States.

Density
489/km²
people per km²
Founded
1900

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

Temperature in January

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 56°F in the first days to 59°F by the end.

A typical January day in Hercules reaches about 57°F in the afternoon and slips back to 42°F overnight — a 15°F spread between the day's warmth and the night's chill. On most days the high lands between 52°F and 64°F. Set against its neighbours, January runs on par with December and about 3°F cooler than February.

30°40°50°60°70°151015202531
Avg high (°F)Avg low (°F)
15641
25641
35641
45641
55641
65641
75641
85642
95742
105742
115742
125742
135742
145742
155742
165742
175742
185742
195842
205842
215842
225842
235842
245842
255842
265943
275943
285943
295943
305943
315943

Hercules weather by month

How January compares with the rest of the year at a glance. January is the 11th-warmest and 2nd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan57° / 42°4.09.39.74.2
Feb61° / 44°4.28.810.55.0
Mar64° / 46°3.18.711.76.1
Apr68° / 48°1.44.9137.3
May74° / 52°0.73148.4
Jun79° / 55°0.20.814.68.9
Jul80° / 56°0.00.114.49.0
Aug81° / 56°0.00.213.58.9
Sep81° / 55°0.10.412.38.8
Oct75° / 52°0.93118.5
Nov65° / 46°1.95.69.96.5
Dec57° / 42°3.79.39.44.3

Cloud cover in January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 32% of the time in January, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 11% of January, with mostly cloudy or overcast conditions the remaining 57%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14258
24159
34060
44060
54159
64159
74159
84159
94159
104258
114258
124159
134258
144357
154357
164456
174456
184456
194456
204456
214456
224555
234456
244357
254456
264456
274456
284456
294456
304456
314456

Chance of precipitation in January

Any precipitation

Hercules gets around 4.0 in of rain over 9.3 wet days in January. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 30% and peaks near 31% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
130
230
330
430
530
630
729
829
929
1029
1129
1230
1330
1430
1530
1631
1731
1831
1931
2031
2131
2231
2331
2430
2530
2629
2729
2828
2928
3027
3127

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 99% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
1982
2982
3991
4991
5991
6991
7991
8991
9991
10991
11991
12991
13991
14991
15991
16991
17991
18991
19991
20991
21991
22991
23991
24991
25991
26991
27991
28991
29991
30991
31991

Wind in January

Winds average 5 mph in January.

Across January, daily wind ranges from about 5 mph on the calmest days to 5 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
185calm
195calm
205calm
215calm
225calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm
315calm

Sunrise & sunset in January

DaylightNight

Daylight runs from about 9 h 24 min at the start of January to 10 hours by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 36 minutes over January. Sunrise moves from 7:30 AM to 7:22 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)
19.47:304:54
29.47:304:55
39.47:314:56
49.47:314:57
59.47:314:57
69.57:314:58
79.57:314:59
89.57:315:00
99.57:315:01
109.57:315:02
119.57:305:03
129.67:305:04
139.67:305:05
149.67:305:05
159.67:305:06
169.67:295:07
179.77:295:08
189.77:295:09
199.77:285:10
209.77:285:11
219.77:285:13
229.87:275:14
239.87:275:15
249.87:265:16
259.97:265:17
269.97:255:18
279.97:245:19
289.97:245:20
2910.07:235:21
3010.07:225:22
3110.07:225:23

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 2.29 kWh/m².

For context, solar energy here swings from a low near 2.13 kWh/m² to a high of 7.96 kWh/m² in June across the year — January's 2.29 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.2Moderate
22.2Moderate
32.2Moderate
42.2Moderate
52.2Moderate
62.2Moderate
72.2Moderate
82.2Moderate
92.2Moderate
102.2Moderate
112.2Moderate
122.2Moderate
132.2Moderate
142.2Moderate
152.3Moderate
162.3Moderate
172.3Moderate
182.3Moderate
192.4Moderate
202.4Moderate
212.4Moderate
222.4Moderate
232.5Moderate
242.5Moderate
252.5Moderate
262.6Moderate
272.6Moderate
282.6Moderate
292.7Moderate
302.7Moderate
312.7Moderate
Planning a trip in January

Hazard calendar for Hercules

In seasonPeak

In January, Hercules sits inside its rainy season season. The full year is below, with each hazard's peak months called out.

Hercules's rainy season runs November–March, when most of the year's rain falls.

Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is January a good time to visit Hercules?

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

4.2
Sightseeing
12th-best month of the year
0.0
Beach & pool
12th-best month of the year

January is a reasonable time to visit Hercules for sightseeing.

What to pack for Hercules in January

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

In January, Hercules sees daytime highs around 57°F and nights near 42°F. Worth packing: a warm layer and rain gear. About 9 days see rain.

a warm layerrain gear

Sea temperature near Hercules in January

The nearest coast averages about 53°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 21 mi away) is warmest in September at about 58°F and coldest in April near 53°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
Jan53Bracing
Feb53Bracing
Mar54Bracing
Apr53Bracing
May53Bracing
Jun54Bracing
Jul56Bracing
Aug58Bracing
Sep58Bracing
Oct57Bracing
Nov55Bracing
Dec54Bracing

UV index in Hercules in January

LowModerateHighVery highExtreme

Clear-sky midday UV in January peaks around 2. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Hercules peaks around July 11 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 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 highHighModerateJul 11UV 10Dec 15UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar5Moderate
Apr6High
May8Very high
Jun10Extreme
Jul10Extreme
Aug10Very high
Sep6High
Oct5High
Nov2Moderate
Dec2Low

Air quality in Hercules 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 Hercules is worst in September — around 29 µg/m³ PM2.5 (moderate), about 4.2× the cleanest month (June, 7 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

010203040JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateSep 1829 µg/m³Jun 127 µg/m³
PM2.5 (µg/m³)Level
Jan13Moderate
Feb13Moderate
Mar13Moderate
Apr10Good
May8Good
Jun7Good
Jul10Good
Aug25Moderate
Sep29Moderate
Oct27Moderate
Nov16Moderate
Dec12Good
Location & terrain

Where is Hercules?

Hercules sits at 38.0°N, 122.3°W, 79 ft above sea level, in United States. The nearest listed city is Pinole, 1.2 mi away.

Topography around Hercules

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Hercules.

Within 2 miles, the terrain around Hercules has only modest variations in elevation — a maximum elevation change of 564 ft around an average of 75 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,126 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 4,459 ft.

The land around Hercules is covered by water (41%) and artificial surfaces (36%) within 2 miles, water (41%), grassland (20%) and artificial surfaces (20%) within 10 miles, and water (28%), grassland (27%) and trees (23%) within 50 miles.

2 miles
564 ft
10 miles
2,126 ft
50 miles
4,459 ft
treesshrubsgrasslandcroplandartificial surfacesbare terrainwaterwetland
January weather nearby: Pinole 1.2 mi · San Pablo 5.0 mi · Vallejo 6.2 mi · Richmond 6.2 mi · El Cerrito 6.8 mi · Benicia 7.5 mi · Martinez 8.7 mi · Albany 8.7 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 Hercules (38.0171°, -122.2886°, elevation 79 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).