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San Diego in December: weather, sea & travel advice
This month's data profile
Clear transition month
San Diego in December is climatically well suited to active holidays and hiking and city breaks. The average daily high is around 18 °C, and the sea is about 16 °C. With about 5 rainy days it is dry.
Historical monthly averages, not a weather forecast. Individual days and years can differ substantially.
Rank among 12 monthly averages
64/100 · #10
Warmth
#11
Dryness
#9
Sun
#12
Sea warmth
#9
Published best categories: none
San Diego · DecemberPhoto: Rufustelestrat · CC BY 2.5Climate facts
- Average high
- 18 °C
- Average low
- 9 °C
- Sea
- 16 °C
- Rainy days (est.)
- 5 rainy days (est.)
- Sun (est.)
- 4 h/day
- Humidity
- 64 %
Climate evidence with direct month comparison
The highlighted row is the selected month. Precipitation total and rainy days are separate monthly averages.
| Month | Avg high °C | Avg low °C | Rainy days (est.) | Precipitation mm | Sun h/day (est.) | Humidity % | Wind m/s | Sea °C | Score |
|---|---|---|---|---|---|---|---|---|---|
| November | 21 | 11 | 4 | 21 | 4.8 | 59 | 2.3 | 17 | 78 |
| December (selected) | 18 | 9 | 5 | 42 | 3.9 | 64 | 2.5 | 16 | 64 |
| January | 18 | 9 | 6 | 54 | 4.3 | 65 | 2.5 | 15 | 62 |
How do the previous and next months compare?
Baseline: December (64/100)
Positive and negative values show the change from the selected month.
| Score Δ | Average high Δ | Average low Δ | Rainy days Δ | Rain Δ | Sun Δ | Humidity Δ | Wind Δ | Sea Δ | |
|---|---|---|---|---|---|---|---|---|---|
| November | +14 | +3.6 °C | +2.7 °C | -1.6 | -20.3 mm | +0.9 h | -4.3 % | -0.2 m/s | +1.5 °C |
| January | -2 | ±0 °C | -0.1 °C | +1.1 | +12.2 mm | +0.4 h | +1.1 % | ±0 m/s | -0.7 °C |
All twelve months in context
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Frequently asked questions
How warm is San Diego in December?
The average daily high is around 18 °C, with an average daily low of about 9 °C.
Can you swim in San Diego in December?
The sea is about 16 °C (cold).
Does it rain a lot in San Diego in December?
The curated estimate is about 5 rainy days per month, not a directly measured long-term average. Total precipitation averages around 42 mm for the month. A rainy day does not mean all-day rain.
When is the best time to visit San Diego?
By the climate score, May, June, September and October are the strongest months for San Diego. For a beach trip: June, July, August and September. December is not among them.