San Diego weather in December
December in San Diego: nice, a little rain, with very humid — a good time to visit.
#12 of 12 months in San Diego · #338 of 604 destinations to visit in December · comfort 68/100 (tier C)
Updated June 2026 · climate normals from ERA5 reanalysis
San Diego climate normals — December
| Daytime high | 18°C / 64°F | 😎 nice |
|---|---|---|
| Nighttime low | 10°C / 50°F | |
| Feels like (high) | 16°C / 61°F | |
| Rainfall | 60 mm / 2.4 in | 🌦 some rain |
| Rainy days | 6 days | |
| Humidity | 78% | 💦 very humid |
| Dew point | 9°C / 49°F | |
| Sunshine | 7.9 h/day | |
| Daylight | 10 h | |
| Wind | 14 km/h / 9 mph | |
| Air quality (US AQI) | 66 | 🙂 moderate |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
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San Diego in December — FAQ
- Is December a good time to visit San Diego?
- December in San Diego: nice, a little rain, with very humid — a good time to visit. It ranks #12 of 12 months for San Diego on SeasonMap's comfort score (68/100).
- What is the weather like in San Diego in December?
- In December, San Diego averages a daily high of 17.6°C and a low of 9.8°C, with about 59.7 mm of rain over roughly 6 rainy days.
- What is the air quality in San Diego in December?
- San Diego has a mean US Air Quality Index of about 66 in December.