San Bernardino, CA weather in December
San Bernardino is mild and mostly dry in December: highs average 67°F and nights drop to about 40°F. Expect about 6 wet days. It is one of the coolest months in San Bernardino. A good month for most outdoor plans.
- Normal high
- 67°F
- Normal low
- 40°F
- Wet days
- 6
- 2.0 in total
- Muggy days
- 0
- dew point 65°F+
How December changes from start to finish
| December 1 | December 31 | |
|---|---|---|
| Normal high | 70°F | 66°F |
| Normal low | 41°F | 40°F |
| Chance of a wet day | 17% | 21% |
| Sunrise / sunset | 6:36 am / 4:39 pm | 6:54 am / 4:49 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 am42°Fdew point 32°F
- 9 am52°Fdew point 34°F
- Noon63°Fdew point 30°F
- 3 pm64°Fdew point 30°F
- 6 pm54°Fdew point 33°F
- 9 pm49°Fdew point 33°F
NOAA hourly normals (local standard time) from March AFB (15 mi away); average wind 5 mph; clear or few clouds in 61% of daytime hours, mostly cloudy or overcast in 31%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F15 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 in4 of 31
- Freezing nightslow 32°F or below1 of 31
Average days per December, counted from daily records for each year 1991-2020.
Rain in December
Normal precipitation is 2.0 in; a dry December brings about 0.5 in and a wet one about 2.8 in (25th and 75th percentiles). About 1 day brings half an inch or more. Snow is very rare.
How December varies from year to year
- Warmest December, 1991-20202000: average high 72°F
- Coolest December1992: average high 61°F
- Wettest December2010: 12.6 in
- Driest December2017: no measurable precipitation
- Highest reading87°F (December 4, 2007)
- Lowest reading27°F (December 23, 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 | 75°F | 67°F | 67°F |
| Normal low | 45°F | 40°F | 41°F |
| Wet days | 4 | 6 | 7 |
| Comfortable days | 16 | 15 | 17 |
| Daylight | 10.4 h | 9.9 h | 10.2 h |
Highs change by -8°F from November and 0°F into January.
Nearby alternatives in December
- Drier: Palm Springs, CA47 mi · high 69°F · 2 wet days
- Cooler: Big Bear Lake, CA24 mi · high 46°F · 5 wet days
How San Bernardino ranks in December
- Normal high55th warmest of 378 cities; 20th of 60 in California
- Wet days73rd driest of 378
- Comfortable days33rd most of 340
What to pack for San Bernardino in December
- A warm jacket – lows near 40°F, highs near 67°F
- Layers – afternoons near 67°F but nights near 40°F
Frost in December
The first fall frost typically comes around Dec 19; in 1 year in 10 it comes before Dec 1. All frost dates for San Bernardino.
Heating and cooling
December has 363 heating degree days and 1 cooling degree days (base 65°F), 11% of the year's total heating and cooling demand.
Questions
How cold is San Bernardino in December?
The normal high is 67°F and the normal low is 40°F. From 1991 to 2020 the coldest December reading was 27°F (December 23, 1998).
Does it rain a lot in San Bernardino in December?
About 6 days in December have at least 0.01 in of precipitation, and the normal total is 2.0 in. The wettest December in 1991-2020 was in 2010 (12.6 in); the driest was in 2017, with no measurable precipitation.
Does it snow in San Bernardino in December?
Snow is very rare: the 1991-2020 normal for December rounds to 0.0 in.
Is December a good time to visit San Bernardino?
December ranks 7th of 12 months on our comfort score for San Bernardino (64 out of 100). It has about 15 comfortable days. The best months are March, April and May.
Where the numbers come from
- Temperature, rain, snowfall, snow depth and frost dates: Redlands (USC00047306), 7.3 mi SE of the city center, 1,410 ft (359 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour and cloud cover: March AFB (USW00023119), 15 mi S of the city center, 1,516 ft (465 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: March Air Reserve Base (722860-23119), 15 mi S of the city center, 1,536 ft (485 ft higher than the city). Hourly observations, 1991-2020.