Rancho Santa Margarita weather in December

In December, Rancho Santa Margarita sees average daytime highs of 64°F and overnight lows near 44°F, with 2.5 in of rain across 5.3 wet days and about 9.8 hours of daylight. It is the 12th-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 66°F in the first days to 63°F by the end. The sky is clear or mostly clear about 52% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 54 min at the start of December to 9 h 48 min by month's end. Set against the rest of the year, December is Rancho Santa Margarita's 9th-clearest and 6th-windiest month. For the whole year in context, see Rancho Santa Margarita's year-round climate.

Daytime high
64°
12th warmest
Overnight low
44°
2nd coldest
Rainfall
2.5 in
5.3 wet days
Daylight
9 h 48 min
6:53 AM – 4:40 PM
Cloud cover
42%
9th clearest
Wind
4 mph
6th windiest
Solar energy
2.99 kWh/m²
Travel score
6.6
out of 10

Rancho Santa Margarita is city in Orange County, California, United States.

Density
1,466/km²
people per km²
Founded
2000

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

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 66°F in the first days to 63°F by the end.

A typical December day in Rancho Santa Margarita reaches about 64°F in the afternoon and slips back to 44°F overnight — a 20°F spread between the day's warmth and the night's chill. On most days the high lands between 55°F and 73°F. Set against its neighbours, December runs about 7°F cooler than November and on par with January.

30°40°50°60°70°80°151015202531
Avg high (°F)Avg low (°F)
16646
26646
36545
46545
56545
66545
76545
86445
96444
106444
116444
126444
136444
146344
156343
166343
176343
186343
196343
206343
216343
226342
236342
246342
256342
266342
276342
286342
296342
306342
316342

Rancho Santa Margarita weather by month

How December compares with the rest of the year at a glance. December is the 12th-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan64° / 44°3.66.4106.5
Feb64° / 46°4.46.810.76.4
Mar67° / 48°2.66.511.76.9
Apr71° / 51°1.23.912.87.9
May74° / 56°0.62.313.78.7
Jun80° / 60°0.10.614.28.6
Jul86° / 65°0.10.6146.7
Aug88° / 66°0.10.313.26.1
Sep85° / 64°0.21.312.26.9
Oct79° / 57°0.92.811.28.5
Nov70° / 49°1.23.210.38.0
Dec64° / 44°2.55.39.86.6

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 52% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 11% of December, with mostly cloudy or overcast conditions the remaining 37%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16832
26733
36733
46634
56535
66535
76436
86436
96436
106337
116337
126337
136337
146436
156436
166436
176436
186436
196436
206436
216436
226337
236337
246238
256238
266139
276139
286040
295941
305941
315941

Chance of precipitation in December

Any precipitation

Rancho Santa Margarita gets around 2.5 in of rain over 5.3 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 17% and peaks near 20% on the wettest days.

0%10%20%30%151015202531
Rain chance (%)
115
215
315
416
516
616
716
816
917
1017
1117
1217
1317
1417
1517
1618
1718
1818
1918
2018
2118
2218
2318
2418
2518
2618
2718
2819
2919
3020
3120

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

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
1982
2982
3982
4982
5982
6982
7982
8982
9991
10991
11991
12991
13991
14991
15991
161000
171000
181000
191000
201000
211000
221000
231000
241000
251000
261000
271000
281000
29991
30991
31991

Wind in December

Winds average 4 mph in December.

Across December, daily wind ranges from about 4 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
64calm
74calm
84calm
94calm
104calm
114calm
124calm
134calm
144calm
154calm
164calm
174calm
184calm
194calm
204calm
214calm
224calm
234calm
244calm
254calm
264calm
274calm
284calm
294calm
304calm
314calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 54 min at the start of December to 9 h 48 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 6:42 AM to 7:00 AM, and sunset from 4:38 PM to 4:47 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.96:424:38
29.96:434:38
39.96:444:38
49.96:454:38
59.96:464:38
69.96:464:38
79.86:474:38
89.86:484:38
99.86:494:38
109.86:494:38
119.86:504:39
129.86:514:39
139.86:514:39
149.86:524:39
159.86:534:40
169.86:534:40
179.86:544:40
189.86:544:41
199.86:554:41
209.86:554:41
219.86:564:42
229.86:564:42
239.86:574:43
249.86:574:43
259.86:584:44
269.86:584:44
279.86:594:45
289.86:594:46
299.86:594:46
309.86:594:47
319.87:004:47

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.99 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.99 kWh/m² to a high of 7.98 kWh/m² in June across the year — December's 2.99 kWh/m² sits near the bottom.

01234151015202531
Solar energy (kWh/m²)Level
13.1Moderate
23.1Moderate
33.1Moderate
43.0Moderate
53.0Moderate
63.0Moderate
73.0Moderate
83.0Moderate
93.0Moderate
102.9Moderate
112.9Moderate
122.9Moderate
132.9Moderate
142.9Moderate
152.9Moderate
162.9Moderate
172.9Moderate
182.9Moderate
192.9Moderate
202.9Moderate
212.9Moderate
222.9Moderate
233.0Moderate
243.0Moderate
253.0Moderate
263.0Moderate
273.0Moderate
283.0Moderate
293.0Moderate
303.0Moderate
313.0Moderate
Planning a trip in December

Is December a good time to visit Rancho Santa Margarita?

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

6.6
Sightseeing
9th-best month of the year
2.0
Beach & pool
11th-best month of the year

December is a reasonable time to visit Rancho Santa Margarita for sightseeing.

What to pack for Rancho Santa Margarita in December

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

In December, Rancho Santa Margarita sees daytime highs around 64°F and nights near 44°F. Worth packing: a warm layer. About 5 days see rain.

a warm layer

Sea temperature near Rancho Santa Margarita in December

The nearest coast averages about 60°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 16 mi away) is warmest in August at about 69°F and coldest in February near 59°F.

It's comfortable for a long swim from Jul 13 to Sep 28 — about 2.6 months when the water holds above 68°F.

60°65°70°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingcomfortable to swim
Sea temperature (°F)Comfort
Jan59Cool
Feb59Cool
Mar59Cool
Apr60Cool
May63Cool
Jun65Cool
Jul68Refreshing
Aug69Refreshing
Sep69Refreshing
Oct67Cool
Nov64Cool
Dec60Cool

UV index in Rancho Santa Margarita 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 Rancho Santa Margarita peaks around June 23 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 16 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateVery highExtremeVery highHighModerateJun 23UV 10Dec 16UV 3
UV index (midday)Level
Jan4Moderate
Feb5Moderate
Mar5Moderate
Apr8Very high
May8Very high
Jun11Extreme
Jul10Extreme
Aug10Extreme
Sep8Very high
Oct6High
Nov3Moderate
Dec3Moderate

Air quality in Rancho Santa Margarita 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 Rancho Santa Margarita is worst in September — around 49 µg/m³ PM2.5 (poor), about 4.0× the cleanest month (May, 12 µg/m³).

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

0204060JanFebMarAprMayJunJulAugSepOctNovDecModeratePoorModerateSep 1447 µg/m³May 1713 µg/m³
PM2.5 (µg/m³)Level
Jan18Moderate
Feb19Moderate
Mar19Moderate
Apr17Moderate
May12Moderate
Jun17Moderate
Jul19Moderate
Aug32Moderate
Sep49Poor
Oct21Moderate
Nov21Moderate
Dec18Moderate
Location & terrain

Where is Rancho Santa Margarita?

Rancho Santa Margarita sits at 33.6°N, 117.6°W, 948 ft above sea level, in United States. The nearest listed city is Mission Viejo, 5.0 mi away.

Topography around Rancho Santa Margarita

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

Within 2 miles, the terrain around Rancho Santa Margarita has only modest variations in elevation — a maximum elevation change of 764 ft around an average of 1,007 ft above sea level; within 10 miles, very significant variations in elevation — a maximum elevation change of 5,564 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 9,967 ft.

The land around Rancho Santa Margarita is covered by artificial surfaces (41%) and trees (35%) within 2 miles, trees (43%) and artificial surfaces (21%) within 10 miles, and water (27%) and artificial surfaces (25%) within 50 miles.

2 miles
764 ft
10 miles
5,564 ft
50 miles
9,967 ft
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
December weather nearby: Mission Viejo 5.0 mi · Lake Forest 5.0 mi · Ladera Ranch 5.0 mi · Laguna Hills 6.8 mi · Laguna Woods 7.5 mi · Aliso Viejo 8.7 mi · Stonegate 9.3 mi · Laguna Niguel 9.9 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 Rancho Santa Margarita (33.6409°, -117.6031°, elevation 948 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).