San Diego weather in December
Temperature, sea and sunshine in December: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in December
Poor
Best time to visit: July – September
What is the weather like in San Diego in December?
In December, San Diego is mild: daytime highs average 17 °C, and nights cool down to about 9 °C. The sea averages 16.0 °C – swimming is only for the hardy. The sun shines for around 8 hours a day. Rain falls on about 6 days, adding up to 54 mm. All in all, December is not an ideal month for a holiday in San Diego.
December compared
How the weather changes from November to January. Tap a month to open it.
| NovemberNov | DecemberDec | JanuaryJan | |
|---|---|---|---|
| Score | 48 | 33 | 34 |
| Day | 20° | 17° | 17° |
| Night | 12° | 9° | 9° |
| Sea | 17° | 16° | 15° |
| Sun | 9 h | 8 h | 8 h |
| Rain days | 4 | 6 | 6 |
More details for December
- Daylight
- 10 h 1 min06:43 – 16:44
- UV index
- 3 · moderateclear sky, noon (estimate)
- Muggy days
- 0 daysdew point 18 °C or more
- Wind
- 14 km/haverage daily peak
- Cloud cover
- 45 %on average
- Hot days
- 0 days30 °C or more
- Time zone
- UTC−8America/Los_Angeles
How the score comes together
- Temperatureweight 35 %0 %
- Seaweight 25 %0 %
- Sunshineweight 20 %75 %
- Few rainy daysweight 20 %89 %
Each factor is rated from 0 to 100 % and weighted for the travel style “Sun, sea & sand”.
What to pack in December
- A jumper for the evenings
San Diego in December: quick answers
Is San Diego hot in December?
No. In December, San Diego is mild: daytime highs average 17 °C and nights drop to about 9 °C.
Can you swim in San Diego in December?
Only if you don't mind cold water: in December the sea averages just 16.0 °C. Comfortable swimming is possible from July to September.
Does it rain much in San Diego in December?
Rain falls on about 6 days, adding up to 54 mm.
San Diego month by month
The whole year in San DiegoAll destinations: USA
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, GeoNames (CC BY 4.0)