How Many Sunny Days Does San Francisco Get Per Year?
San Francisco, California has a very mild climate. The average temperature is relatively consistent year round so that it’s never too hot or too cold. In addition to that, the city gets significantly more sunshine than most cities in the US. How many sunny days in San Francisco can you expect? And how often does it rain? Let’s together examine the average weather you can encounter in San Francisco.
To create this article, I used climate data from the National Weather Service, an organization within the NOAA (National Oceanic and Atmospheric Administration).
Here’s the Number of Sunny Days in San Francisco, California
According to the NOAA, downtown San Francisco receives 3,062 sunshine hours a year. These numbers will be relatively similar for other nearby places in Bay Area (though the further away from the Pacific Ocean we go, the more different these numbers will be).
What do these sunshine hours mean if we’re looking to calculate the number of sunny days in San Francisco?
Here’s how often you can expect sun in every month of the year in the Golden Gate Bridge city:
Month | Sunshine hours | Percent possible sunshine | Average sunny days |
---|---|---|---|
January | 185.9 | 61% | 18.91 |
February | 207.7 | 69% | 19.32 |
March | 269.1 | 73% | 22.63 |
April | 309.3 | 78% | 23.4 |
May | 325.1 | 74% | 22.94 |
June | 311.4 | 70% | 21 |
July | 313.3 | 70% | 21.7 |
August | 287.4 | 68% | 21.08 |
September | 271.4 | 73% | 21.9 |
October | 247.1 | 71% | 22.01 |
November | 173.4 | 57% | 17.1 |
December | 160.6 | 54% | 16.74 |
According to this data, San Francisco has about 249 sunny days per year. This number includes both partly sunny days as well as clear days. (Downtown) San Francisco thus has 116 cloudy days which is roughly one third of the year. This makes SF’s mild weather even more appealing as it’s not only moderate but also sunny.
The sunniest month in San Francisco is April with 23 days of sun. Other very sunny months are March and May.
The least sunny month is December with 17 days of sun. This is also the second coldest month after January with an average temperature reaching just 58 °F during the day and only 47 °F at night.
Sunshine Hours in San Francisco Compared to Other Cities
Despite its famous fog, San Francisco is still one of the sunniest cities in the United States. It’s also unique in that it has both a moderate climate and plenty of sun. Usually sunny cities don’t have such a mild climate but a rather hot one, particularly in the summer months.
But let’s see how San Francisco’s sunshine hours (3,062) compare to other US cities.
San Diego gets almost the same amount of sunshine, recording 3,054 hours of sun. San Francisco is less sunny than Los Angeles which has 3,254 hours of sunshine. It’s also much less sunny than Sacramento which gets 3,608 hours of sun and which is a common example of a hot city having plenty of sun (as opposed to San Francisco’s moderate climate).
Because there’s no sunshine data available for other San Francisco Bay Area cities, unfortunately I can’t compare SF with them. So let’s leave Bay Area and California and check other regions of the country.
If we go north, we can compare San Francisco to other temperate (but bit colder) cities on the Pacific Ocean or nearby. For example, Seattle is much cloudier than SF. It gets only 2,170 hours of sunshine, meaning it doesn’t have particularly sunny weather. Portland is a little better as it records 2,341 hours of sunshine.
On the other extreme are cities in Arizona, Nevada, and Texas. Compared to San Francisco, weather in these places is completely different. This applies both to the number of sunshine hours as well as the extremely high average high temperature these cities record in the summer months.
I’m talking about Las Vegas with 3,825 hours of sun, Reno with 3,646, Phoenix with 3,872, Tucson with 3,806, and El Paso with 3,763. Average high temperatures in all these cities do or may climb to 100 °F which is an extreme difference compared to San Francisco’s mellow 70 °F in the hottest month.
San Francisco may not be as sunny as the hottest cities but it’s definitely much sunnier than cool weather cities on the east coast. No city gets even close. Boston gets 2,634 hours of sunshine, New York City gets 2,535, Washington, D.C. 2,528, Chicago 2,508, and Philadelphia 2,498.
San Francisco is even sunnier than warm weather Jacksonville, Florida (which records 2,880 hours of sun a year). SF isn’t sunnier than Miami, though, which gets 3,154 hours of sunshine a year.
How Many Days of Rain Does San Francisco Get?
San Francisco is not only known for its mild temperatures, the Golden Gate Bridge, and some famous neighborhoods. It’s also known for its fog, which brings us to… rainfall.
Here’s how many days of rain you can expect in San Francisco per year:
Month | Rainy days |
---|---|
January | 11.2 |
February | 10.8 |
March | 10.8 |
April | 6.8 |
May | 4 |
June | 1.6 |
July | 0.7 |
August | 1.1 |
September | 1.2 |
October | 3.5 |
November | 7.9 |
December | 11.6 |
In total, San Francisco records 71 days of rain a year. Compared to San Francisco, weather is much less rainy in Los Angeles (34 rainy days) and San Diego (40 rainy days). The annual rainfall in San Francisco is also much higher than in these two cities, reaching almost 23 inches compared to 14 in Los Angeles and 10 in San Diego.
Because of the city’s Mediterranean climate, it experiences the wettest weather during the winter months. Summers are very dry with very little rainfall.
Further Reading
If you’re interested in more articles about the climate in California, check out my articles: