San Francisco climate
San Francisco (California, United States) has a warm-summer Mediterranean climate (Köppen Csb). The average temperature over the year is 14 °C57 °F, and about 586 mm23 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
San Francisco climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin |
|---|---|---|---|---|
| Jan | 1356 | 643 | 1050 | 1003.9 |
| Feb | 1458 | 745 | 1151 | 1024.0 |
| Mar | 1661 | 846 | 1253 | 823.2 |
| Apr | 1763 | 847 | 1355 | 421.6 |
| May | 1966 | 1050 | 1458 | 180.7 |
| Jun | 2271 | 1152 | 1662 | 60.2 |
| Jul | 2272 | 1254 | 1763 | 10.0 |
| Aug | 2373 | 1355 | 1864 | 10.0 |
| Sep | 2474 | 1254 | 1864 | 40.1 |
| Oct | 2171 | 1152 | 1661 | 291.2 |
| Nov | 1763 | 947 | 1355 | 622.4 |
| Dec | 1456 | 744 | 1050 | 1385.4 |
| Year | 2474 | 643 | 1457 | 58623 |
“Year” row: highest monthly high, lowest monthly low, annual mean and annual total.
| Month | Humid. | Cloud | Solar | Daylight |
|---|---|---|---|---|
| Jan | 84% | 58% | 2.5 | 9:49 |
| Feb | 82% | 58% | 3.4 | 10:44 |
| Mar | 82% | 58% | 4.6 | 11:51 |
| Apr | 80% | 53% | 6.0 | 13:08 |
| May | 78% | 51% | 6.7 | 14:12 |
| Jun | 74% | 44% | 7.3 | 14:46 |
| Jul | 74% | 56% | 6.5 | 14:32 |
| Aug | 74% | 57% | 5.8 | 13:36 |
| Sep | 70% | 46% | 5.1 | 12:22 |
| Oct | 69% | 44% | 4.0 | 11:08 |
| Nov | 76% | 50% | 2.8 | 10:04 |
| Dec | 82% | 59% | 2.1 | 9:34 |
Humid. = average relative humidity at 2 m; cloud = average cloud amount; solar = average daily solar energy reaching the ground in kWh/m² (all-sky); daylight in hours:minutes, calculated for the 15th of each month.
What the climate of San Francisco is like
The warmest month is September, with an average high of 24 °C74 °F and a low of 12 °C54 °F. The coldest is January, when highs average 13 °C56 °F and lows 6 °C43 °F. There is a clear seasonal cycle, with 8.2 °C14.8 °F between the average temperature of the warmest and the coolest month.
Annual precipitation is moderate at about 586 mm23 in. The wettest three-month stretch is December–February, which brings 58% of the annual total. Months with less than 20 mm0.8 in on average: May–September. The wettest month is December (138 mm5.4 in), the driest is August (1 mm0.0 in).
Relative humidity ranges from 69% in October to 84% in January. The clearest skies (lowest average cloud amount, 44%) are typical of October. Average wind speed near the ground ranges from 7 km/h (4 mph) in October to 9 km/h (6 mph) in May. Daylight lasts from about 9.6 hours in December to 14.8 hours in June.
Best time to visit San Francisco
Based on these averages, the most comfortable months for sightseeing and outdoor activities are May–October: average highs of 19 °C66 °F to 24 °C74 °F with 1 mm0.0 in to 29 mm1.2 in of precipitation per month.
Comfort score: months are ranked by how close they come to an average high of 21–28 °C (70–82 °F), lows above 5 °C (41 °F), little precipitation and moderate humidity. The best-ranked months of each place are recommended, even where none meets all of these. These are general rules of thumb applied to long-term averages.
What to pack for San Francisco
- Winter (December–February) — highs 1356 to 14 °C58 °F, lows 643 to 7 °C45 °F, about 113 mm4.5 in of precipitation a month. Pack long sleeves, a sweater and a medium jacket and an umbrella or light rain jacket.
- Spring (March–May) — highs 1661 to 19 °C66 °F, lows 846 to 10 °C50 °F, about 47 mm1.9 in of precipitation a month. Pack long sleeves, a sweater and a medium jacket.
- Summer (June–August) — highs 2271 to 23 °C73 °F, lows 1152 to 13 °C55 °F, about 3 mm0.1 in of precipitation a month. Pack light layers — T-shirts plus a light sweater or jacket and an extra layer for the cooler mornings and evenings.
- Autumn (September–November) — highs 1763 to 24 °C74 °F, lows 947 to 12 °C54 °F, about 32 mm1.2 in of precipitation a month. Pack light layers — T-shirts plus a light sweater or jacket and an extra layer for the cooler mornings and evenings.
How San Francisco compares
Compared with San Jose, about 67 km to the southeast, San Francisco is on average 1.3 °C2.3 °F cooler and receives 15% more precipitation (586 mm23 in vs 511 mm20 in). The difference is largest in July (3.7 °C6.7 °F cooler).
Of the 222 places in the United States covered by World Climates, San Francisco is the 122nd warmest by annual mean temperature and the 155th wettest by annual precipitation. See all of them on the United States climate page.
Places in other countries with the most similar temperature and rainfall pattern (seasons shifted for the other hemisphere where needed): Valparaíso (Chile, BSk), Amadora (Portugal, Csb) and Lisbon (Portugal, Csb).
The same NASA POWER grid cell also contains Oakland (pop. 419,267), Berkeley (pop. 120,972) and Richmond (pop. 109,708). Their long-term averages in this dataset are essentially the same as for San Francisco, so they do not have separate pages.
Nearby places
- Daly City 9 km · 13 °C55 °F · 516 mm20 in
- Hayward 32 km · 15 °C59 °F · 511 mm20 in
- Vallejo 39 km · 14 °C57 °F · 586 mm23 in
- Concord 41 km · 15 °C59 °F · 467 mm18 in
- Antioch 60 km · 15 °C60 °F · 467 mm18 in
- Fairfield 62 km · 15 °C60 °F · 467 mm18 in
- San Jose 67 km · 15 °C60 °F · 511 mm20 in
- Santa Rosa 78 km · 16 °C61 °F · 688 mm27 in
Frequently asked questions
What is the warmest month in San Francisco?
September is the warmest month in San Francisco, with an average high of 24 °C (74 °F) and an average low of 12 °C (54 °F).
What is the coldest month in San Francisco?
January is the coldest month, with an average high of 13 °C (56 °F) and an average low of 6 °C (43 °F).
When does it rain the most in San Francisco?
December is the wettest month with about 138 mm (5.4 in) of precipitation; August is the driest with about 1 mm (0.0 in).
What is the best time to visit San Francisco?
Judging by long-term averages, the most comfortable months are May–October.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station, so they can differ from airport records — most of all on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.
The grid cell’s average elevation is 87 m, while San Francisco lies at about 16 m. Temperatures on this page were therefore adjusted by +0.5 °C0.8 °F using the standard lapse rate of 6.5 °C per 1,000 m.