Costa Mesa, CA weather in December
December in Costa Mesa: mild and mostly dry. Highs 68°F, lows 48°F, rain on about 6 days. It is one of the coolest months in Costa Mesa. A great month for outdoor plans.
- Normal high
- 68°F
- Normal low
- 48°F
- Wet days
- 6
- 1.6 in total
- Muggy days
- 0
- dew point 65°F+
How December changes from start to finish
| December 1 | December 31 | |
|---|---|---|
| Normal high | 70°F | 69°F |
| Normal low | 49°F | 48°F |
| Chance of a wet day | 16% | 20% |
| Sunrise / sunset | 6:38 am / 4:43 pm | 6:56 am / 4:53 pm |
| Daylight | 10.1 h | 9.9 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Pacific Time).
A typical December day
- 6 am51°Fdew point 39°F
- 9 am57°Fdew point 39°F
- Noon64°Fdew point 39°F
- 3 pm63°Fdew point 43°F
- 6 pm59°Fdew point 45°F
- 9 pm57°Fdew point 44°F
NOAA hourly normals (local standard time) from Los Angeles Intl Airport (34 mi away); average wind 6 mph; clear or few clouds in 39% of daytime hours, mostly cloudy or overcast in 38%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F22 of 31
- Beach dayshigh 80-95°F, under 0.05 in of rain, afternoon wind under 15 mph2 of 31
- Hot dayshigh 90°F or more0 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow6 of 31
- Notable rainat least 0.10 in3 of 31
- Freezing nightslow 32°F or below0 of 31
Average days per December, counted from daily records for each year 1991-2020.
Rain in December
Normal precipitation is 1.6 in; a dry December brings about 0.4 in and a wet one about 2.2 in (25th and 75th percentiles). About 1 day brings half an inch or more.
How December varies from year to year
- Warmest December, 1991-20202017: average high 75°F
- Coolest December2012: average high 64°F
- Wettest December1997: 6.8 in
- Driest December1999: no measurable precipitation
- Highest reading90°F (December 12, 2010)
- Lowest reading25°F (December 10, 1998)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
December compared with November and January
| November | December | January | |
|---|---|---|---|
| Normal high | 74°F | 68°F | 69°F |
| Normal low | 53°F | 48°F | 49°F |
| Wet days | 3 | 6 | 7 |
| Comfortable days | 20 | 22 | 20 |
| Daylight | 10.4 h | 10.0 h | 10.2 h |
Highs change by -6°F from November and +1°F into January.
Nearby alternatives in December
- Drier: Palm Springs, CA80 mi · high 69°F · 2 wet days
- Cooler: Oceanside, CA44 mi · high 63°F · 5 wet days
How Costa Mesa ranks in December
- Normal high37th warmest of 378 cities; 6th of 60 in California
- Wet days64th driest of 378
- Comfortable days3rd most of 340
Heating and cooling
December has 214 heating degree days and 5 cooling degree days (base 65°F), 10% of the year's total heating and cooling demand.
Questions
How cold is Costa Mesa in December?
The normal high is 68°F and the normal low is 48°F. From 1991 to 2020 the coldest December reading was 25°F (December 10, 1998).
Does it rain a lot in Costa Mesa in December?
About 6 days in December have at least 0.01 in of precipitation, and the normal total is 1.6 in. The wettest December in 1991-2020 was in 1997 (6.8 in); the driest was in 1999, with no measurable precipitation.
Is December a good time to visit Costa Mesa?
December ranks 6th of 12 months on our comfort score for Costa Mesa (73 out of 100). It has about 22 comfortable days. The best month is May.
Where the numbers come from
- Temperature: Santa Ana Fire Stn (USC00047888), 7.7 mi NNE of the city center, 135 ft . NOAA normals and daily records, 1991-2020.
- Rain, snowfall and snow depth: Newport Beach Harbor (USC00046175), 3.3 mi SE of the city center, 10 ft (90 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Frost dates: Santa Ana John Wayne Airport (USW00093184), 4.0 mi NE of the city center, 54 ft . NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour and cloud cover: Los Angeles Intl Airport (USW00023174), 34 mi NW of the city center, 97 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: J. Wayne Apt-Orange Co Apt (722977-93184), 4.0 mi NE of the city center, 43 ft (57 ft lower than the city). Hourly observations, 1991-2020.