San Luis Obispo weather in December

In December, San Luis Obispo sees average daytime highs of 60°F and overnight lows near 47°F, with 3.0 in of rain across 6.6 wet days and about 9.7 hours of daylight. It is the 11th-warmest and 3rd-wettest month of the year here.

Day-to-day highs hold fairly steady near 60°F through the month. The sky is clear or mostly clear about 47% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 48 min at the start of December to 9 h 42 min by month's end. Set against the rest of the year, December is San Luis Obispo's 9th-clearest and 5th-windiest month. For the whole year in context, see San Luis Obispo's year-round climate.

Daytime high
60°
11th warmest
Overnight low
47°
2nd coldest
Rainfall
3.0 in
6.6 wet days
Daylight
9 h 36 min
7:10 AM – 4:48 PM
Cloud cover
46%
9th clearest
Wind
7 mph
5th windiest
Solar energy
2.76 kWh/m²
Travel score
5.3
out of 10

San Luis Obispo is county seat of San Luis Obispo County, California, United States.

Density
1,414/km²
people per km²
Founded
1772

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 60°F through the month.

A typical December day in San Luis Obispo reaches about 60°F in the afternoon and slips back to 47°F overnight — a 12°F spread between the day's warmth and the night's chill. On most days the high lands between 54°F and 66°F. Set against its neighbours, December runs about 5°F cooler than November and on par with January.

40°50°60°70°151015202531
Avg high (°F)Avg low (°F)
16149
26149
36149
46149
56149
66048
76048
86048
96048
106048
116048
126048
136048
146048
155947
165947
175947
185947
195947
205947
215947
225947
235947
245947
255947
265947
275947
285947
295947
305947
315947

San Luis Obispo 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
Jan60° / 47°3.97.29.95.2
Feb60° / 48°3.77.610.75.1
Mar61° / 49°2.86.211.75.8
Apr63° / 51°1.03.412.96.9
May65° / 53°0.41.513.87.8
Jun69° / 56°0.10.414.38.6
Jul71° / 58°0.00.114.19.0
Aug72° / 59°0.00.113.39.2
Sep72° / 59°0.00.412.29.1
Oct70° / 56°0.8211.18.5
Nov64° / 51°1.33.610.17.1
Dec60° / 47°3.06.69.75.3

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 47% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 14% of December, with mostly cloudy or overcast conditions the remaining 39%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16535
26436
36436
46337
56337
66337
76238
86139
96139
106139
116040
126040
136139
146139
156139
166139
176139
186139
196139
206139
216238
226238
236139
246139
256040
266040
276040
285941
295941
305941
315842

Chance of precipitation in December

Any precipitation

San Luis Obispo gets around 3.0 in of rain over 6.6 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 21% and peaks near 23% on the wettest days.

0%10%20%30%151015202531
Rain chance (%)
118
219
319
420
520
620
720
821
921
1021
1121
1221
1321
1421
1521
1621
1721
1821
1921
2021
2121
2222
2322
2422
2522
2622
2723
2823
2923
3023
3123

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 98% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
1964
2964
3964
4964
5964
6964
7964
8964
9964
10973
11973
12973
13973
14982
15982
16982
17982
18982
19991
20991
21991
22991
23991
24991
25991
26991
27982
28982
29982
30982
31982

Wind in December

Winds average 7 mph in December.

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

0246810151015202531
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm
317calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 48 min at the start of December to 9 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 6 minutes over December. Sunrise moves from 6:59 AM to 7:16 AM, and sunset from 4:46 PM to 4:55 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.86:594:46
29.86:594:46
39.87:004:46
49.77:014:46
59.77:024:46
69.77:034:46
79.77:044:46
89.77:044:46
99.77:054:46
109.77:064:46
119.77:074:47
129.77:074:47
139.77:084:47
149.67:094:47
159.67:094:47
169.67:104:48
179.67:104:48
189.67:114:48
199.67:124:49
209.67:124:49
219.67:134:50
229.67:134:50
239.67:144:51
249.67:144:51
259.67:144:52
269.67:154:52
279.67:154:53
289.67:154:53
299.67:164:54
309.67:164:55
319.77:164:55

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.76 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.76 kWh/m² to a high of 8.19 kWh/m² in June across the year — December's 2.76 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.9Moderate
22.9Moderate
32.8Moderate
42.8Moderate
52.8Moderate
62.8Moderate
72.8Moderate
82.7Moderate
92.7Moderate
102.7Moderate
112.7Moderate
122.7Moderate
132.7Moderate
142.7Moderate
152.7Moderate
162.7Moderate
172.7Moderate
182.7Moderate
192.7Moderate
202.7Moderate
212.7Moderate
222.7Moderate
232.7Moderate
242.7Moderate
252.8Moderate
262.8Moderate
272.8Moderate
282.8Moderate
292.8Moderate
302.8Moderate
312.8Moderate
Planning a trip in December

Is December a good time to visit San Luis Obispo?

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

5.3
Sightseeing
10th-best month of the year
0.3
Beach & pool
11th-best month of the year

December is a reasonable time to visit San Luis Obispo for sightseeing.

What to pack for San Luis Obispo in December

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

In December, San Luis Obispo sees daytime highs around 60°F and nights near 47°F. Worth packing: a warm layer. About 7 days see rain.

a warm layer

Sea temperature near San Luis Obispo in December

The nearest coast averages about 57°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 11 mi away) is warmest in September at about 60°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°62°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°F)Comfort
Jan56Bracing
Feb56Bracing
Mar55Bracing
Apr54Bracing
May54Bracing
Jun55Bracing
Jul58Bracing
Aug59Cool
Sep60Cool
Oct60Cool
Nov58Bracing
Dec57Bracing

UV index in San Luis Obispo in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 3. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in San Luis Obispo peaks around June 22 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJun 22UV 11Dec 15UV 3
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar5Moderate
Apr7High
May8Very high
Jun11Extreme
Jul10Extreme
Aug10Extreme
Sep8Very high
Oct6High
Nov3Moderate
Dec3Moderate

Air quality in San Luis Obispo 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 Luis Obispo is worst in August — around 19 µg/m³ PM2.5 (moderate), about 4.5× the cleanest month (June, 4 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodAug 2218 µg/m³Jun 124 µg/m³
PM2.5 (µg/m³)Level
Jan7Good
Feb6Good
Mar7Good
Apr6Good
May5Good
Jun4Good
Jul7Good
Aug19Moderate
Sep17Moderate
Oct7Good
Nov6Good
Dec5Good
Location & terrain

Where is San Luis Obispo?

San Luis Obispo sits at 35.3°N, 120.7°W, 233 ft above sea level, in United States. The nearest listed city is Arroyo Grande, 12 mi away.

Topography around San Luis Obispo

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

Within 2 miles, the terrain around San Luis Obispo has significant variations in elevation — a maximum elevation change of 1,572 ft around an average of 420 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,861 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 5,407 ft.

The land around San Luis Obispo is covered by grassland (39%), artificial surfaces (36%) and trees (20%) within 2 miles, grassland (44%) and trees (41%) within 10 miles, and grassland (50%) and water (25%) within 50 miles.

2 miles
1,572 ft
10 miles
2,861 ft
50 miles
5,407 ft
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
December weather nearby: Arroyo Grande 12 mi · Atascadero 14 mi · Nipomo 19 mi · Paso Robles 24 mi · Santa Maria 26 mi · Orcutt 32 mi · Lompoc 46 mi · Coalinga 62 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 Luis Obispo (35.2828°, -120.6596°, elevation 233 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).