San Francisco weather in January
Temperature, sea and sunshine in January: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in January
Fair
Best time to visit: April – October
What is the weather like in San Francisco in January?
In January, San Francisco is cool: daytime highs average 14 °C, and nights cool down to about 6 °C. The sea averages 11.7 °C – swimming is only for the hardy. Expect around 5 hours of sunshine a day. Rain falls on about 9 days, adding up to 89 mm. All in all, January is a so-so month for a holiday in San Francisco.
January compared
How the weather changes from December to February. Tap a month to open it.
| DecemberDec | JanuaryJan | FebruaryFeb | |
|---|---|---|---|
| Score | 52 | 54 | 62 |
| Day | 14° | 14° | 15° |
| Night | 7° | 6° | 7° |
| Sea | 12° | 12° | 12° |
| Sun | 5 h | 5 h | 6 h |
| Rain days | 10 | 9 | 9 |
More details for January
- Daylight
- 9 h 49 min07:24 – 17:13
- UV index
- 2 · lowclear sky, noon (estimate)All months
- Muggy days
- 0 daysdew point 18 °C or more
- Wind
- 14 km/haverage daily peak
- Cloud cover
- 62 %on average
- Hot days
- 0 days30 °C or more
- Time zone
- UTC−8America/Los_Angeles
How the score comes together
- Temperatureweight 50 %57 %
- Sunshineweight 20 %32 %
- Few rainy daysweight 30 %65 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in January
- A jumper for the evenings
- Rain jacket or umbrella
San Francisco in January: quick answers
Is San Francisco hot in January?
No. In January, San Francisco is cool: daytime highs average 14 °C and nights drop to about 6 °C.
Can you swim in San Francisco in January?
Only if you don't mind cold water: in January the sea averages just 11.7 °C. Comfortable swimming temperatures are not reached at any time of year.
Does it rain much in San Francisco in January?
Rain falls on about 9 days, adding up to 89 mm.
San Francisco month by month
The whole year in San FranciscoAll destinations: USAWhere to go in JanuarySea temperature in January
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0)