San Francisco has a mild, 'Mediterranean' climate with cool, rainy winters and dry, warm summers. The city has a respectable average of 263 sunny days a year and temperatures typically range from 40 to 70 degrees Fahrenheit (4 to 21 degrees Celsius). The city has low levels of precipitation, receiving an average of 23 inches (58.4 cm) of rain annually. Snow is rare in San Francisco, but it does occur occasionally in the higher elevations of the city.
San Francisco is a coastal city, so it experiences strong winds and fog throughout the year. Located in an area known as the 'fog belt', this means the city experiences foggy conditions more often than other parts of the state. The fog is most common during the summer months, although it can occur at any time of year. This fog is a result of the combination of the city's location by the ocean and its hilly topography.
Climate change is having a significant impact on San Francisco. As temperatures rise and snowfall decreases, the city is experiencing more extreme weather events, such as heat waves and droughts. In addition, rising sea levels are threatening the city's coastline, leading to increased flooding and erosion.
The bar chart below shows the average monthly peak daytime temperatures at San Francisco
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
°C | 13.2 | 15.3 | 15.8 | 16.9 | 17.9 | 19.2 | 19.8 | 20.1 | 21.4 | 20.6 | 16.8 | 13.5 |
°F | 55.8 | 59.6 | 60.4 | 62.4 | 64.1 | 66.5 | 67.6 | 68.2 | 70.5 | 69.1 | 62.2 | 56.3 |
Please note: these are the average peak daytime temperatures (usually around mid-afternoon) so do not show daytime / night highs and lows. To see the daily range of temperatures have a look at the temperature max / min chart below.
The graph below shows the average rainfall and number of rainy days per month.
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
mm | 125 | 91 | 89 | 40 | 7 | 4 | 1 | 2 | 7 | 35 | 90 | 97 |
inches | 4.9 | 3.6 | 3.5 | 1.6 | 0.3 | 0.1 | 0.1 | 0.1 | 0.3 | 1.4 | 3.5 | 3.8 |
Rainy days | 10 | 9 | 11 | 6 | 3 | 1 | 1 | 1 | 2 | 4 | 8 | 10 |
Average annual rainfall in San Francisco: 502.233mm (197.7 inches)
The bar chart below shows the average daily sunshine hours in San Francisco
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Hrs sunshine | 6.4 | 7.9 | 9.3 | 11 | 11.4 | 11.4 | 11.1 | 10.2 | 9.9 | 8.7 | 6.4 | 5.7 |
The graph below shows the daily range of temperatures for each month.
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Min °C | 6.6 | 8.3 | 8.5 | 9.1 | 10 | 11.3 | 11.9 | 12.5 | 13 | 12 | 9.7 | 7.2 |
Max °C | 13.4 | 15.5 | 16 | 17.1 | 18.1 | 19.4 | 20 | 20.3 | 21.6 | 20.8 | 17 | 13.7 |
Min °F | 43.9 | 46.9 | 47.2 | 48.4 | 49.9 | 52.3 | 53.3 | 54.5 | 55.4 | 53.6 | 49.4 | 44.9 |
Max °F | 50 | 53.4 | 54 | 55.6 | 57.2 | 59.5 | 60.6 | 61.5 | 63.1 | 61.5 | 55.9 | 50.7 |
The graph below shows the average sea temperature.
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
°C | 12.4 | 12.2 | 12.2 | 11.8 | 11.8 | 12.2 | 13.1 | 14 | 14.4 | 14.2 | 13.6 | 12.7 |
°F | 54.2 | 54 | 53.9 | 53.3 | 53.2 | 53.9 | 55.5 | 57.2 | 57.9 | 57.6 | 56.4 | 54.9 |
The graph below shows the average wind speed.
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
km/h | 12 | 14 | 17 | 19 | 21 | 21 | 20 | 19 | 17 | 14 | 13 | 13 |
mph | 8 | 9 | 11 | 12 | 13 | 13 | 13 | 12 | 10 | 9 | 8 | 8 |
A monthly average windspeed of over 16km/h or 10mph suggests a location is fairly windy.
The graph below shows the average relative humidity.
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
---|---|---|---|---|---|---|---|---|---|---|---|
79% | 77% | 73% | 70% | 70% | 69% | 70% | 72% | 70% | 71% | 76% | 79% |
Hottest month: | September | 21.4°C 70.5°F |
---|---|---|
Driest month: | July | 1mm 0ins |
Sunniest month: | April | 11hrs |
Coldest month: | January | 13.2°C 55.8°F |
Wettest month: | January | 125mm 4.9ins |
Warmest sea: | September | 14.4°C 57.9°F |