Climate averages 1991–2020
San Diego weather
in December.
A mild, moderately wet month: the 11th warmest and the 10th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
December is a mild month in San Diego: daytime highs average 17.3°C and nights cool to about 8.8°C. By daytime temperature it is the 11th warmest of the 12 months.
Expect about 40 mm of rain on roughly 5 days, which makes December a moderately wet month (the 10th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 10 h 03 min on an average December day.
The nearest other city in this atlas is Chula Vista (11 km away). In December its highs average 17.0°C, about as warm as San Diego, with 47 mm of rain.
Among the 498 cities listed in the United States, San Diego ranks joint 95th of 498 for the warmest December highs and 81st of 498 for the driest December (rainfall, lowest first). The mean December high of those 498 cities is 10.5°C; San Diego is 6.8°C warmer than that mean.
From December to January, average highs rise by 0.1°C to 17.4°C, and monthly rainfall rises from 40 mm to 50 mm.
The annual picture
December in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
San Diego climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 17.4°C8.7°C | 8.7°C | 50 | 5.5 | 10.310 h |
| February | 17.2°C9.2°C | 9.2°C | 63 | 6.1 | 11.011 h |
| March | 17.8°C10.4°C | 10.4°C | 38 | 5.2 | 12.012 h |
| April | 19.1°C11.9°C | 11.9°C | 16 | 2.9 | 13.013 h |
| May | 20.2°C13.6°C | 13.6°C | 7.1 | 1.6 | 13.814 h |
| June | 22.0°C14.9°C | 14.9°C | 1.2 | 0.2 | 14.314 h |
| July | 24.3°C17.1°C | 17.1°C | 1.3 | 0.3 | 14.114 h |
| August | 25.4°C18.0°C | 18.0°C | 0.4 | 0.1 | 13.413 h |
| September | 25.1°C17.5°C | 17.5°C | 2.9 | 0.6 | 12.412 h |
| October | 23.0°C15.2°C | 15.2°C | 12 | 2.0 | 11.411 h |
| November | 20.3°C11.7°C | 11.7°C | 19 | 2.9 | 10.511 h |
| December, selected | 17.3°C8.8°C | 8.8°C | 40 | 4.9 | 10.010 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
December in nearby cities
- Chula Vista in DecemberUnited States · 11 kmHigh 17.0°C · Low 9.4°C · 47 mm rain
- El Cajon in DecemberUnited States · 21 kmHigh 17.7°C · Low 7.9°C · 47 mm rain
- Tijuana in DecemberMexico · 28 kmHigh 16.8°C · Low 9.0°C · 51 mm rain
- Rosarito in DecemberMexico · 41 kmHigh 17.1°C · Low 9.9°C · 44 mm rain
- Escondido in DecemberUnited States · 45 kmHigh 17.4°C · Low 5.7°C · 59 mm rain
- San Marcos in DecemberUnited States · 48 kmHigh 16.7°C · Low 6.2°C · 54 mm rain
- Vista in DecemberUnited States · 54 kmHigh 17.6°C · Low 6.6°C · 54 mm rain
- Oceanside in DecemberUnited States · 57 kmHigh 16.9°C · Low 8.6°C · 46 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for San Diego) is explained once on the San Diego year overview and on the Sources, method and limits page.