San Francisco features a mild, maritime climate with cool summers and mild, wet winters. Temperatures remain steady year-round, rarely experiencing extremes. The city is famous for its persistent fog, microclimates, and refreshing breezes from the Pacific Ocean. Sunshine, rain, and fog can all occur in a single day, making weather here famously unpredictable.
The best times to travel section shows how the months compare for a visit, so you can find the time of year that fits what you want to do.
Background colours of the months:
The colour shows the typical temperature: yellow (hot), green (mild) and blue (cold). How strong the colour is shows the travel season: full colour means high season, soft colour means shoulder season and soft-striped means off season.
Weather symbols:
Each month has one symbol showing what the weather is typically like, such as hot and sunny, freezing or a rainy or snowy season. Use them to quickly spot months that match the weather you want, or to avoid the ones that don't.
Crowdedness:
The people icon shows how busy the place usually is. The more people, the more crowded it gets.
Additional notes:
The grey info boxes point out special things worth knowing, like recurring weather issues or seasonal events.
San Francisco’s climate is classified as warm-summer Mediterranean, shaped by the cold Pacific currents and coastal geography. Summers (June to September) are cool and dry, with average highs of 18–21°C and frequent morning fog, especially near the coast and Golden Gate Bridge. The fog typically lifts by afternoon, revealing clear skies and sunshine. Nights are always cool, often dropping to 12–14°C, so layers are essential. The city’s microclimates mean temperatures can vary significantly between neighbourhoods, with downtown and eastern areas often sunnier and warmer than the foggy western districts.
Winters (December to February) are mild but wetter, with average highs around 13–15°C and lows near 7–9°C. Rain is most common from November to March, peaking in January, though rainfall is generally moderate and heavy storms are rare. Snow is extremely rare. Spring (March to May) and autumn (September to November) are transitional, with mild temperatures, occasional rain, and less fog than summer. Autumn is often the warmest and sunniest time of year, with September typically the warmest month. San Francisco receives about 3,000 hours of sunshine annually, but sunshine hours drop to 5–6 per day in winter. Winds are a constant feature, especially in spring and summer, with speeds of 16–32 km/h common along the coast and in exposed areas.
The Pacific Ocean remains cold year-round, with sea temperatures ranging from 12°C in winter to 14°C in late summer. The city’s weather is famously unpredictable – locals say you can experience all four seasons in a single day. Always check the forecast and dress in layers to adapt to changing conditions.
| Average climate data for San Francisco, United States | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Average maximum temperature (°C) | 13 | 14 | 16 | 17 | 19 | 21 | 22 | 22 | 23 | 20 | 16 | 13 | 23 |
| Average minimum temperature (°C) | 8 | 8 | 8 | 9 | 10 | 12 | 13 | 14 | 14 | 13 | 10 | 8 | 8 |
| Average precipitation (mm) | 26 | 34 | 22 | 7 | 9 | 3 | 2 | 2 | 2 | 9 | 21 | 26 | 163 |
| Average rainfall days (days) | 8 | 6 | 9 | 5 | 4 | 2 | 2 | 3 | 2 | 4 | 5 | 8 | 58 |
| Average relative humidity (%) | 72 | 75 | 77 | 73 | 73 | 70 | 72 | 74 | 69 | 67 | 71 | 73 | 72 |
| Average wind speed (km/h) | 9 | 11 | 12 | 12 | 12 | 12 | 10 | 10 | 9 | 9 | 9 | 10 | 10 |
| Average water temperature (°C) | 12 | 12 | 12 | 12 | 12 | 12 | 13 | 14 | 14 | 14 | 13 | 13 | 13 |
| Average daily daylight hours (h) | 9 | 10 | 12 | 13 | 14 | 14 | 14 | 13 | 12 | 11 | 10 | 9 | 12 |
| Average daily sunshine hours (h) | 6 | 6 | 7 | 10 | 10 | 11 | 11 | 11 | 10 | 7 | 6 | 5 | 8 |
| Average cloud coverage (%) | 33 | 30 | 35 | 26 | 25 | 17 | 14 | 16 | 14 | 18 | 26 | 35 | 24 |
| Average UV index | 3 | 3 | 4 | 5 | 4 | 5 | 5 | 5 | 5 | 4 | 3 | 3 | 4 |
The best time to visit San Francisco is from September to early November, when the city enjoys its warmest, sunniest weather, minimal fog, and fewer crowds. Spring (April–May) is also pleasant, with mild temperatures and blooming parks. Both seasons offer comfortable conditions for sightseeing and outdoor activities.
The least favourable time to visit is during winter (December to February), when rain is most frequent and sunshine hours are shortest. Although temperatures remain mild, wet and windy days can limit outdoor activities. Summer can also be unexpectedly chilly and foggy, especially near the coast.
San Francisco has a mild, maritime climate with cool summers and mild, wet winters. Temperatures are steady throughout the year, and the city is famous for its fog and microclimates.
September and October are typically the warmest and sunniest months in San Francisco, with daytime highs reaching 21–23°C and less fog than during the summer.
Snow is extremely rare in San Francisco, with only a few recorded events in the city’s history. Winter temperatures rarely drop below 5°C, making snow almost impossible.
Fog is most common in summer, especially in the mornings and near the coast. It usually lifts by afternoon. Other seasons see less fog, with autumn being the clearest.
San Francisco receives most of its rain from November to March, with January being the wettest month. Annual rainfall averages around 600 mm, and summer is typically very dry.
Dress in layers and bring a warm jacket, even in summer. Pack a raincoat for winter and spring. Comfortable shoes and sun protection are recommended year-round due to the city’s hills and variable weather.
The Pacific Ocean near San Francisco remains cold year-round, with temperatures between 12–14°C. Swimming is possible but usually requires a wetsuit due to the chilly water.
The warmest month, with the highest average maximum temperature, is September (22.8 °C). The month with the lowest average maximum temperature is December (13.1 °C). Overall, the average maximum temperature over the whole year is 18.2 °C.
The month with the highest average minimum temperature is September (13.8 °C). The coldest month, with the lowest average minimum temperature, is January (7.6 °C). Overall, the average minimum temperature over the whole year is 10.5 °C.
The month with the highest average water temperature is September (14.2 °C). The month with the lowest average water temperature is May (11.6 °C). Overall, the average water temperature over the whole year is 12.6 °C.
The wettest month, with the highest amount of precipitation, is February (34.5 mm). The driest month, with the least amount of precipitation, is August (2 mm). Over the whole year there are 163.3 mm of rainfall on average.
The month with the most days of rain is March (9.4 days). The month with the fewest days of rain is June (1.8 days). Over the whole year there are 58.4 days of rain on average.
The month with the highest average relative humidity is March (77.1 %). The month with the lowest average relative humidity is October (66.6 %). The overall average relative humidity over the whole year is 72 %.
The windiest month, with the highest average wind speed, is May (12.2 km/h). The calmest month, with the lowest average wind speed, is November (8.8 km/h). The overall average wind speed over the whole year is 10.4 km/h.
The month with the cloudiest skies, so the highest cloud coverage, is December (35.3 %). The month with the clearest skies, so the lowest cloud coverage, is September (13.8 %). Over the whole year there is an average cloud coverage of 24.2 %.
The month with the longest days, so the most daylight, is June (Average daylight: 14.1 h). The month with the shortest days, so the least daylight, is December (Average daylight: 9.1 h). Over the whole year there are 11.8 h of daylight per day on average.
The month with the most sunshine per day is July (Average sunshine: 11.2 h). The month with the least sunshine per day is December (Average sunshine: 5 h). Over the whole year there are 8.4 h of sunlight per day on average.
The months with the highest average UV index are April, June, July, August and September (UV index: 5). The months with the lowest average UV index are January, February, November and December (UV index: 3). Over the whole year the average UV index is 4.1.
