San Diego Weather in December
What's the weather like in San Diego (Calabarzon) in December 2025?
The climate in San Diego during December can be summarized as hot, humid and very wet.
December is in the winter in San Diego and is typically the 2nd coldest month of the year. Daytime maximum temperatures average around a steamy 29°C (83°F), whilst at night 22°C (72°F) is normal.
| Daytime temperature | 28.6°C 83.4°F |
|---|---|
| Nightly temperature | 22.1°C 71.7°F |
| Average temperature | 25.3°C 77.5°F |
| Daily sunshine | 5.7 hrs |
| Avg rainfall | 310 mm 12.2 ins |
| Rainy days | 18 days |
| Sea temperature | 28.1°C 82.5°F |
| Humidity | 84% |
| Windspeed | 10.1kph 6 mph |
On average December is the 3rd wettest month of the year in San Diego with around 310mm 12.2 inches of rain making it a very wet time to visit. This rainfall is typically spread over 18 days, although this may vary considerably.
On the flip side this corresponds to an average of 5.7 hours of sunshine per day.
December temperatures in San Diego
December rainfall
December hourly sunshine
The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in San Diego in December 2025.
Other monthly averages
Best places to visit in December
San Diego weather stats
| Hottest month: | May | 32.9°C 91.2°F |
|---|---|---|
| Driest month: | March | 71mm 2.8ins |
| Sunniest month: | April | 9hrs |
| Coldest month: | January | 28.3°C 82.9°F |
| Wettest month: | October | 406mm 16ins |
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