San Francisco, California, offers a unique climate that attracts visitors year-round.
The city experiences mild temperatures with little variation, ranging from 45.9°F to 72.5°F throughout the year. This steady weather makes it a pleasant destination regardless of the season.
Check out the detailed climate data to see the monthly averages for temperature and humidity.
Rainfall in San Francisco is fairly consistent, with the city receiving about 23.66 inches of rain annually.
There are around 68 days of precipitation each year, balanced by approximately 2950 hours of sunshine. This combination ensures that whether you’re exploring downtown or enjoying the bay views, you’ll experience both the fog and the sun that define this iconic city.
San Francisco’s weather is influenced by its proximity to the Pacific Ocean.
The coolest water temperatures occur in April at 53°F, while the warmest is in September at 58°F, making it an interesting phenomenon for beachgoers and marine enthusiasts.
For more details, explore the weather conditions recorded at San Francisco International Airport.
Average Temperature in San Francisco, California
San Francisco has mild weather year-round with limited temperature extremes. In January, the coldest month, the average temperature is around 51°F.
The average low for this month is 44°F, and the average high is 58°F.
In contrast, September is the warmest month. During this month, the average high reaches around 70°F, while the average low is about 57°F.
June, July, and August see moderate summer temperatures.
Daily highs during these months typically reach the mid-60s°F, ensuring mild weather.
Here’s a breakdown of average high and low temperatures:
| Month | Average High (°F) | Average Low (°F) |
|---|---|---|
| January | 58 | 44 |
| February | 60 | 48 |
| March | 62 | 49 |
| April | 63 | 50 |
| May | 63 | 52 |
| June | 67 | 54 |
| July | 67 | 55 |
| August | 69 | 55 |
| September | 70 | 57 |
| October | 68 | 55 |
| November | 63 | 50 |
| December | 58 | 45 |
Throughout the year, temperatures rarely exceed 70°F or dip below 44°F, keeping the weather fairly consistent.
Even in December, one of the colder months, temperatures generally remain mild.
Average Precipitation in San Francisco, California
San Francisco experiences a distinct pattern of precipitation, characterized by moderate rainfall concentrated in the winter months and virtually no snowfall.
Average Rainfall in San Francisco, California
San Francisco’s rainfall is mostly concentrated from November to March. The city receives an average of about 23 inches of rain annually.
The wettest month is usually January, with around 4.5 inches of rainfall.
December and February also see significant precipitation, with roughly 4.3 and 4 inches, respectively.
Rainy days are common in these months, averaging about 10 to 12 days with measurable precipitation.
In the summer, rain is rare, with July and August often seeing less than 0.1 inches of rain.
The dry periods contribute to a consistent pattern, making San Francisco’s weather predictably moist in the winter and dry in the summer.
Average Snow in San Francisco, California
Snow in San Francisco is almost nonexistent. The city’s moderate climate and coastal location prevent snowfall.
The few instances recorded in history are rare events, occurring less than once every few decades.
Consequently, snow and ice conditions are not a concern for residents or visitors.
Despite the scarcity of snow, cooler temperatures can be expected in the winter, often accompanied by rain rather than snow.
The mild conditions are a stark contrast to other parts of California, offering a unique climate profile.
This absence of snowfall makes planning winter activities in the city straightforward, without the need for snow-related preparations.
Average Sun in San Francisco, California
San Francisco experiences a moderate amount of sunshine throughout the year, with clear skies and plenty of daylight. The city enjoys varying levels of sunlight depending on the season.
Average Daily Shortwave Solar Energy in San Francisco, California
San Francisco receives a fair amount of daily shortwave solar energy, which is energy from the sun that reaches the earth’s surface.
The amount of solar energy varies by month, with the summer months typically receiving more energy due to longer daylight hours.
During June, July, and August, the city enjoys around 12 to 14 hours of daylight, contributing to higher levels of sunlight and clearer skies.
In contrast, winter months like December and January have about 9 to 10 hours of daylight, leading to reduced solar energy.
San Francisco’s yearly average of clear skies allows for optimal sunshine hours, totaling roughly 2950 hours annually.
This makes the city suitable for activities requiring sunlight, although the intensity and duration of sunlight can differ dramatically between seasons.
The gradual change in daylight hours impacts daily planning and energy usage throughout the year.
Average Humidity in San Francisco, California
San Francisco experiences varying levels of relative humidity throughout the year. The city’s relative humidity is influenced by its coastal location and the cool breeze from the Pacific Ocean.
Highest Humidity: January and February are the most humid months. January has an average relative humidity of 80%, making it the most humid month.
Lowest Humidity: October has the lowest relative humidity at 71%.
| Month | Average Relative Humidity (%) |
|---|---|
| January | 80 |
| February | 78 |
| March | 76 |
| April | 74 |
| May | 70 |
| June | 68 |
| July | 70 |
| August | 72 |
| September | 73 |
| October | 71 |
| November | 74 |
| December | 79 |
The annual average humidity in San Francisco is around 75%.
This results in a generally mild and moist climate which can affect comfort levels and outdoor activities.
For more detailed information, you can check average humidity in San Francisco, California.
Average Wind in San Francisco, California
San Francisco experiences varying wind speeds throughout the year.
The average wind speed typically ranges between 5 and 15 mph.
The highest wind speeds are usually observed in July, making it the windiest month.
During January, the average wind speed tends to be lower.
| Month | Average Wind Speed (mph) |
|---|---|
| January | ~7 mph |
| July | ~15 mph |
San Francisco’s winds predominantly blow from the west, influenced by the proximity to the Pacific Ocean.
Windy conditions are common, especially near the coast.
For more in-depth information about wind statistics, visit Wind articles.
Average Air Quality in San Francisco, California
San Francisco often enjoys good air quality throughout the year. The city’s Air Quality Index (AQI) typically falls into the “good” category.
This means fine particulate matter (PM2.5) levels range from 0 to 12 μg/m³ most of the time.
In 2019, the average annual PM2.5 concentration in San Francisco was 7.1 μg/m³.
This figure meets the World Health Organization’s air quality guidelines.
Real-time air quality data can be checked using platforms like IQAir and AccuWeather.
Key Parameters
- Average PM2.5 Level: 7.1 μg/m³
- AQI Category: Good
Additional Factors:
- Visibility: Typically clear, but can be affected during wildfire season.
- Cloud Cover: Often varies; fog is common, impacting air clarity.
- Water Temperature: Not directly related to air quality but can be as low as 50°F in coastal areas.
- Pressure: Averages around 30 inches of mercury, influencing weather and pollution dispersion.
To monitor current air quality levels and other weather conditions, such as visibility and cloud cover, real-time maps can be very helpful. These tools provide up-to-date information and help residents make informed decisions.
Topography of San Francisco, California
San Francisco is known for its varied topography, featuring hills, valleys, and coastal areas.
Elevation: The city’s elevation varies greatly. The highest point is Twin Peaks, reaching about 922 feet (281 meters) above sea level.
On average, the city’s elevation is around 52 feet.
Longitude and Latitude: San Francisco lies between 37.64031° to 37.92984° latitude and -122.28002° to -123.17383° longitude.
The coordinates cover the city and its surrounding regions.
Terrain: The city has 43 hills, providing stunning views but also creating challenges.
The steep streets, such as those in Nob Hill and Russian Hill, are famous for their inclines.
Microclimates: The topography, combined with maritime influences, creates distinct microclimates.
Areas near the ocean, like Ocean Beach, are cooler and foggier. In contrast, neighborhoods like Mission District are warmer and drier.
Various Elevations:
- Twin Peaks: Highest point at 922 feet.
- Downtown: Average elevation around 52 feet.
- Treasure Island: Average elevation of 3 feet and a minimum of -49 feet.
The sharp topography also includes undulating terrains and flat areas, enhancing the city’s geographical diversity.
Extreme Weather Events that Occur in San Francisco, California
San Francisco experiences a range of extreme weather events despite its usually mild climate.
One of the most common weather phenomena in San Francisco is fog. The city is known for its foggy conditions, especially during the summer.
The fog often rolls in from the Pacific Ocean, creating cool and misty mornings.
Heatwaves can also occur, although they are relatively rare.
The temperature reached 95°F only 67 times between 1923 and 2023. When temperatures climb above 85°F, there is a noticeable increase in emergency room visits and hospitalizations.
San Francisco can experience freezing temperatures during the winter months.
While snowfall is extremely rare, temperatures can drop below 32°F, potentially causing frost and icy conditions.
Hail is an infrequent event in San Francisco, but it can happen, particularly during thunderstorms.
Hailstones can vary in size and cause damage to property and vegetation.
The table below highlights some of these extreme weather events:
| Weather Event | Details |
|---|---|
| Fog | Frequent, especially in summer |
| Heatwaves | Temps above 85°F increase health risks |
| Freezing Temps | Temps can drop below 32°F in winter |
| Hail | Rare, occurs during thunderstorms |
For more information on the impact of extreme heat on health, you can visit San Francisco’s Extreme Heat and Health report.
Best Time of the Year to Visit San Francisco, California
San Francisco’s climate varies from season to season. Visitors should plan their trips according to their preferences for weather, events, and crowd levels.
What Is San Francisco, California Like in Spring
Spring in San Francisco is characterized by mild temperatures and blooming flowers.
Daytime highs range from the mid-50s to mid-60s Fahrenheit. This season sees occasional rain, especially in March, with an average of 3 to 4 rainy days in April.
Spring visitors can enjoy longer days as daylight saving time starts in March.
This period is less crowded compared to summer, making it a pleasant time for sightseeing.
Popular outdoor activities include visiting Golden Gate Park and hiking in nearby areas.
What Is San Francisco, California Like in Summer
Summer in San Francisco tends to be cool and foggy, particularly in the mornings and evenings.
Temperatures rarely exceed 70°F, with averages in the mid-60s. The city’s iconic fog, known as “Karl the Fog,” often rolls in during these months, especially in June and July.
Despite the cooler weather, summer is peak tourist season, leading to crowded attractions.
Major summer events include the San Francisco Pride Parade in June and the Outside Lands Music and Arts Festival in August.
Visitors should pack layers to stay comfortable in changing weather.
What Is San Francisco, California Like in Fall
Fall is considered the best time to visit San Francisco.
September and October are the warmest months, with average temperatures around 70°F.
These months have the least fog, providing clear blue skies and sunny days.
Crowds are smaller than in summer, making it easier to explore popular sites like Fisherman’s Wharf and Alcatraz Island.
Fall also marks the tail end of daylight saving time, allowing for extended daylight hours.
This season offers a combination of pleasant weather and fewer tourists, making it ideal for travel.
What Is San Francisco, California Like in Winter
Winter in San Francisco is mild and wet.
From November to March, daytime temperatures range from the mid-50s to low 60s.
Rain is common, with the city receiving several inches each month during this period.
While winter is the off-peak tourist season, it can still be enjoyable for visitors who don’t mind the occasional drizzle.
Indoor attractions like museums and theaters offer shelter from the rain.
Winter also has the shortest days of the year, so planning indoor activities in the evenings is recommended.
Winter is less crowded, making it a good choice for budget-conscious travelers.