San Francisco Weather in December
United States · Mediterranean climate · Data averaged from 2020-01-01 to 2024-12-31 (5 years)
December in San Francisco sees average temperatures ranging from a low of 8.1°C (46.6°F) to a high of 13.5°C (56.3°F), with a mean of 10.5°C (50.9°F). Compared to the annual average of 13.5°C (56.3°F), this month is 3.0°C cooler than the yearly norm. Precipitation averages 174.1mm, making it approximately 125.0mm wetter than the monthly average of 49.0mm. This is the wettest month of the year, with 174.1mm of precipitation and around 14.0 rainy days. The city receives an average of 6.4 hours of sunshine per day during December, with relative humidity averaging 83.3%. Wind speeds reach an average maximum of 21.0 km/h. For travelers, this month offers a temperature experience in San Francisco, with wetter-than-average conditions compared to the rest of the year.
If you're planning outdoor activities in San Francisco, ignore the season — focus on the hour. I hiked Lands End in July at 2pm in a t-shirt and was shivering by 4pm when the fog rolled in. The 5°C temperature swing between coast and bay is real. Best running conditions: September-October, when the marine layer retreats and 22°C hits the city. Pack a windbreaker for any coastal trail, year-round. Marin Headlands is magnificent but windy; aim for 10am-2pm. February-March brings surprisingly green hills and empty trails — my favorite hiking window.
December vs Adjacent Months
| Metric | November | December | January |
|---|---|---|---|
| Mean Temp | 12.6°C (54.7°F) | 10.5°C (50.9°F) | 10.5°C (50.9°F) |
| Rainfall | 63.3mm | 174.1mm | 109.2mm |
| Sunshine | 8.5 hrs | 6.4 hrs | 7.0 hrs |
| Humidity | 76.0% | 83.3% | 82.8% |
| Wind | 20.8 km/h | 21.0 km/h | 23.4 km/h |
| Rainy Days | 8.2 | 14.0 | 13.0 |
Seasonal Context
December falls in Winter in the Northern Hemisphere. Winter is the coolest season with the shortest daylight hours. For travelers visiting San Francisco in December, the data indicates mixed conditions based on the combination of temperature, precipitation, and daylight hours.
Frequently Asked Questions
What is the average temperature in San Francisco in December?
The average temperature in San Francisco during December ranges from 8.1°C (46.6°F) to 13.5°C (56.3°F), with a mean of 10.5°C (50.9°F).
How much does it rain in San Francisco in December?
San Francisco receives an average of 174.1mm of precipitation in December, spread across approximately 14.0 rainy days. This is the wettest month of the year.
What should I pack for San Francisco in December?
Based on December weather data, pack warm layers, a medium jacket, and waterproof outerwear. Rain gear is essential — this month averages 174.1mm of precipitation.
Is December a good time to visit San Francisco?
December is a cooler month, suitable for travelers who prefer mild weather and fewer crowds. Pack warm layers and enjoy indoor attractions.
Other Months for San Francisco
Cities with Similar December Climate (Mediterranean)
Data Source: Open-Meteo historical archive (2020-01-01 to 2024-12-31). Daily measurements aggregated into monthly climate normals. Coordinates: 37.77°, -122.42°. Timezone: America/Los_Angeles. Last updated: 2026-07-30.