Rohnert Park weather in January

In January, Rohnert Park sees average daytime highs of 56°F and overnight lows near 42°F, with 5.4 in of rain across 10.3 wet days and about 9.6 hours of daylight. It is the 11th-warmest and 3rd-wettest month of the year here.

Day-to-day highs hold fairly steady near 56°F through the month. 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 Rohnert Park's 12th-clearest and 9th-windiest month. For the whole year in context, see Rohnert Park's year-round climate.

Daytime high
56°
11th warmest
Overnight low
42°
2nd coldest
Rainfall
5.4 in
10.3 wet days
Daylight
9 h 36 min
7:32 AM – 5:08 PM
Cloud cover
60%
12th clearest
Wind
5 mph
9th windiest
Solar energy
2.29 kWh/m²
Travel score
3.9
out of 10

Rohnert Park is city in Sonoma County, California, United States.

Density
2,337/km²
people per km²
Founded
1962

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 56°F through the month.

A typical January day in Rohnert Park reaches about 56°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 51°F and 62°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)
15641
25641
35641
45641
55641
65641
75641
85641
95642
105642
115642
125642
135642
145642
155642
165642
175642
185642
195742
205742
215742
225742
235742
245742
255742
265742
275742
285842
295842
305843
315843

Rohnert Park weather by month

How January compares with the rest of the year at a glance. January is the 11th-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan56° / 42°5.410.39.63.9
Feb59° / 43°5.69.310.54.5
Mar61° / 45°4.29.311.75.3
Apr64° / 47°1.95.6136.5
May68° / 50°1.03.314.17.7
Jun73° / 53°0.2114.69.0
Jul75° / 55°0.00.114.49.5
Aug75° / 55°0.00.213.59.5
Sep75° / 54°0.10.512.39.3
Oct71° / 51°1.23.1118.2
Nov62° / 45°2.86.29.95.9
Dec56° / 42°5.510.49.43.9

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 12% of January, with mostly cloudy or overcast conditions the remaining 56%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14456
24456
34357
44357
54258
64258
74258
84357
94258
104357
114357
124258
134357
144357
154357
164456
174456
184456
194456
204456
214555
224555
234456
244555
254555
264555
274555
284555
294555
304654
314654

Chance of precipitation in January

Any precipitation

Rohnert Park gets around 5.4 in of rain over 10.3 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 33% and peaks near 34% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
132
233
333
433
533
633
733
833
933
1033
1133
1233
1333
1434
1534
1634
1734
1834
1934
2034
2134
2234
2334
2434
2533
2633
2732
2832
2931
3031
3130

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 (%)
1991
2991
3991
4991
5991
6991
7991
8991
9991
10991
11991
12991
13991
14991
15991
16991
17991
18991
19991
20991
21991
22991
23991
241000
251000
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 7:33 AM to 7:24 AM, and sunset from 4:55 PM to 5:24 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.47:334:55
29.47:334:56
39.47:334:57
49.47:334:57
59.47:334:58
69.47:334:59
79.47:335:00
89.57:335:01
99.57:335:02
109.57:335:03
119.57:335:03
129.57:335:04
139.57:335:05
149.67:325:06
159.67:325:07
169.67:325:08
179.67:325:09
189.67:315:10
199.77:315:11
209.77:315:12
219.77:305:13
229.77:305:14
239.87:295:15
249.87:295:17
259.87:285:18
269.97:275:19
279.97:275:20
289.97:265:21
299.97:255:22
3010.07:255:23
3110.07:245:24

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 2.11 kWh/m² to a high of 7.93 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
192.3Moderate
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 Rohnert Park

In seasonPeak

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

Rohnert Park'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 Rohnert Park?

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

3.9
Sightseeing
11th-best month of the year
0.0
Beach & pool
12th-best month of the year

January is a weaker month for outdoor sightseeing in Rohnert Park.

What to pack for Rohnert Park in January

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

In January, Rohnert Park sees daytime highs around 56°F and nights near 42°F. Worth packing: a warm layer and rain gear. About 10 days see rain.

a warm layerrain gear

Sea temperature near Rohnert Park 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 23 mi away) is warmest in September at about 55°F and coldest in May near 51°F.

The water stays below 68°F all year — cool enough that most swimmers want a wetsuit.

50°52°54°56°JanFebMarAprMayJunJulAugSepOctNovDecbracing
Sea temperature (°F)Comfort
Jan53Bracing
Feb53Bracing
Mar53Bracing
Apr51Bracing
May51Bracing
Jun51Bracing
Jul53Bracing
Aug54Bracing
Sep55Bracing
Oct55Bracing
Nov54Bracing
Dec53Bracing

UV index in Rohnert Park 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 Rohnert Park peaks around June 23 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 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 23UV 10Dec 17UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar5Moderate
Apr6High
May9Very high
Jun10Extreme
Jul10Extreme
Aug9Very high
Sep6High
Oct5High
Nov2Moderate
Dec2Low

Air quality in Rohnert Park 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 Rohnert Park is worst in September — around 24 µg/m³ PM2.5 (moderate), about 4.1× the cleanest month (June, 6 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodSep 1623 µg/m³Jun 116 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb9Good
Mar9Good
Apr7Good
May7Good
Jun6Good
Jul9Good
Aug17Moderate
Sep24Moderate
Oct16Moderate
Nov9Good
Dec7Good
Location & terrain

Where is Rohnert Park?

Rohnert Park sits at 38.3°N, 122.7°W, 105 ft above sea level, in United States. The nearest listed city is Santa Rosa, 6.8 mi away.

Topography around Rohnert Park

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

Within 2 miles, the terrain around Rohnert Park has only modest variations in elevation — a maximum elevation change of 253 ft around an average of 128 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,457 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 4,895 ft.

The land around Rohnert Park is covered by artificial surfaces (47%) and grassland (23%) within 2 miles, grassland (47%) and trees (28%) within 10 miles, and trees (34%), water (31%) and grassland (24%) within 50 miles.

2 miles
253 ft
10 miles
2,457 ft
50 miles
4,895 ft
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
January weather nearby: Santa Rosa 6.8 mi · Petaluma 8.1 mi · Agua Caliente 12 mi · Windsor 16 mi · Novato 17 mi · Napa 23 mi · American Canyon 27 mi · San Rafael 27 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 Rohnert Park (38.3396°, -122.7011°, elevation 105 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).