San Rafael weather in December

In December, San Rafael sees average daytime highs of 56°F and overnight lows near 44°F, with 4.4 in of rain across 9.8 wet days and about 9.4 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 35% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 36 min at the start of December to 9 h 24 min by month's end. Set against the rest of the year, December is San Rafael's 10th-clearest and 8th-windiest month. For the whole year in context, see San Rafael's year-round climate.

Daytime high
56°
11th warmest
Overnight low
44°
2nd coldest
Rainfall
4.4 in
9.8 wet days
Daylight
9 h 24 min
7:25 AM – 4:48 PM
Cloud cover
58%
10th clearest
Wind
7 mph
8th windiest
Solar energy
2.13 kWh/m²
Travel score
3.9
out of 10

San Rafael is city and the county seat of Marin County, California, United States.

Density
1,019/km²
people per km²
Founded
1874

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

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 56°F through the month.

A typical December day in San Rafael reaches about 56°F in the afternoon and slips back to 44°F overnight — a 12°F spread between the day's warmth and the night's chill. On most days the high lands between 52°F and 61°F. Set against its neighbours, December runs about 6°F cooler than November and on par with January.

30°40°50°60°70°151015202531
Avg high (°F)Avg low (°F)
15846
25846
35846
45846
55846
65746
75745
85745
95745
105745
115745
125645
135645
145645
155644
165644
175644
185644
195644
205644
215644
225644
235644
245644
255544
265544
275544
285544
295544
305544
315544

San Rafael weather by month

How December compares with the rest of the year at a glance. December 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° / 44°4.59.99.73.9
Feb58° / 46°4.7910.54.4
Mar61° / 48°3.48.811.75.2
Apr63° / 49°1.54.9136.5
May67° / 52°0.83147.6
Jun71° / 54°0.20.814.68.6
Jul72° / 55°0.00.114.48.9
Aug73° / 56°0.00.213.59.0
Sep73° / 55°0.10.412.39.0
Oct70° / 53°1.02.9118.1
Nov62° / 48°2.269.95.9
Dec56° / 44°4.49.89.43.9

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 35% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 12% of December, with mostly cloudy or overcast conditions the remaining 53%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15149
25050
34951
44951
54753
64654
74555
84555
94456
104456
114456
124456
134456
144555
154555
164555
174654
184654
194852
204753
214852
224852
234852
244852
254852
264753
274753
284753
294654
304555
314555

Chance of precipitation in December

Any precipitation

San Rafael gets around 4.4 in of rain over 9.8 wet days in December. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 31% and peaks near 34% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
129
230
330
431
532
632
733
833
934
1034
1134
1234
1334
1433
1533
1632
1732
1832
1931
2031
2131
2230
2330
2430
2530
2630
2730
2830
2930
3030
3131

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, December lands in the dry band about 97% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
1964
2964
3964
4955
5955
6955
7955
8955
9955
10955
11964
12964
13964
14964
15964
16973
17973
18973
19973
20982
21982
22982
23982
24982
25982
26982
27982
28982
29982
30982
31982

Wind in December

Winds average 7 mph in December.

Across December, daily wind ranges from about 6 mph on the calmest days to 7 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm
316calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 36 min at the start of December to 9 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 12 minutes over December. Sunrise moves from 7:13 AM to 7:31 AM, and sunset from 4:47 PM to 4:55 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.67:134:47
29.57:144:46
39.57:154:46
49.57:164:46
59.57:174:46
69.57:184:46
79.57:184:46
89.57:194:46
99.47:204:46
109.47:214:46
119.47:214:47
129.47:224:47
139.47:234:47
149.47:244:47
159.47:244:47
169.47:254:48
179.47:264:48
189.47:264:48
199.47:274:49
209.47:274:49
219.47:284:50
229.47:284:50
239.47:294:50
249.47:294:51
259.47:304:52
269.47:304:52
279.47:304:53
289.47:314:53
299.47:314:54
309.47:314:55
319.47:314:55

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.13 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.13 kWh/m² to a high of 7.85 kWh/m² in June across the year — December's 2.13 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.3Moderate
22.2Moderate
32.2Moderate
42.2Moderate
52.2Moderate
62.1Moderate
72.1Moderate
82.1Moderate
92.1Moderate
102.1Moderate
112.1Moderate
122.1Moderate
132.1Moderate
142.1Moderate
152.1Moderate
162.1Moderate
172.1Moderate
182.1Moderate
192.1Moderate
202.1Moderate
212.1Moderate
222.1Moderate
232.1Moderate
242.1Moderate
252.1Moderate
262.1Moderate
272.1Moderate
282.1Moderate
292.2Moderate
302.2Moderate
312.2Moderate
Planning a trip in December

Hazard calendar for San Rafael

In seasonPeak

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

San Rafael'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 December a good time to visit San Rafael?

Our two travel scores rate December 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
11th-best month of the year

December is a weaker month for outdoor sightseeing in San Rafael.

What to pack for San Rafael in December

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

In December, San Rafael sees daytime highs around 56°F and nights near 44°F. Worth packing: a warm layer and rain gear. About 10 days see rain.

a warm layerrain gear

Sea temperature near San Rafael in December

The nearest coast averages about 54°F in December — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 9 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 San Rafael in December

LowModerateHighVery highExtreme

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

Under clear skies, the midday UV index in San Rafael 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 San Rafael in December

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where December falls, not just the annual average.

Air quality in San Rafael 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 San Rafael?

San Rafael sits at 38.0°N, 122.5°W, 43 ft above sea level, in United States. The nearest listed city is Novato, 9.3 mi away.

Topography around San Rafael

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

Within 2 miles, the terrain around San Rafael has significant variations in elevation — a maximum elevation change of 994 ft around an average of 174 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,808 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 4,459 ft.

The land around San Rafael is covered by trees (62%) and artificial surfaces (31%) within 2 miles, trees (42%) and water (36%) within 10 miles, and water (40%), trees (23%) and grassland (22%) within 50 miles.

2 miles
994 ft
10 miles
2,808 ft
50 miles
4,459 ft
treesgrasslandcroplandartificial surfaceswaterwetland
December weather nearby: Novato 9.3 mi · San Pablo 9.9 mi · Richmond 11 mi · El Cerrito 12 mi · Pinole 13 mi · Hercules 14 mi · Chinatown 14 mi · Albany 14 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 San Rafael (37.9735°, -122.5311°, elevation 43 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).