San Francisco Climate & Monthly Temperature Overview – United States

Spring and Summer

Spring in San Francisco, from March to May, brings mild temperatures averaging between 50 and 65°F (10-18°C), with occasional showers. The iconic fog adds to the city’s charm, but also diminishes sunlight and warmth. Summer, from June to August, remains temperate with average highs of 68°F (20°C). The fog often dissipates in the afternoons, revealing clear skies and warm temperatures perfect for outdoor activities. However, these months also experience the city’s famous “June Gloom,” a period of overcast skies and cool temperatures.

Fall and Winter

Fall in San Francisco, from September to November, showcases warmer days with average highs in the mid-60s (18-19°C) and cool nights. The occasional drizzle adds to the city’s atmosphere, and the fog returns, often enveloping the city in a thick blanket. Winter, from December to February, brings the coldest temperatures of the year. While lows average around 40°F (4°C), highs rarely exceed 55°F (13°C). Despite the chilly weather, the city remains vibrant with holiday events and attractions, although rainfall increases significantly during this time.

Average Temperature in San Francisco, United States

San Francisco, located on the west coast of the United States, boasts a temperate climate characterized by mild temperatures throughout the year. The city’s unique microclimate is attributed to its position between the Pacific Ocean and the San Francisco Bay, which influences the weather patterns. On average, San Francisco experiences a daily high temperature of around 62 degrees Fahrenheit (16 degrees Celsius) and a daily low temperature of approximately 50 degrees Fahrenheit (10 degrees Celsius) throughout the year.

The warmest months in San Francisco are typically September and October, with average high temperatures reaching 70 degrees Fahrenheit (21 degrees Celsius). During these months, the city enjoys plenty of sunshine and warm, pleasant weather. However, the city is known for its unpredictable summer weather, which can sometimes be characterized by chilly and foggy conditions, especially during the mornings and evenings. The winter months (December-February) are mild, with average high temperatures hovering around 55 degrees Fahrenheit (13 degrees Celsius) and average low temperatures dipping to around 40 degrees Fahrenheit (4 degrees Celsius).

Types of Clouds in San Francisco

San Francisco, known for its iconic fog and diverse climate, experiences a range of cloud formations throughout the year. During summer, the city is often blanketed by a thick layer of stratus clouds. These low-level clouds produce a misty, ethereal ambiance that contributes to San Francisco’s unique charm. In autumn and winter, nimbostratus clouds dominate the sky, bringing frequent drizzle and rain. These thick, gray clouds can persist for days, casting a somber mood over the city. However, as the seasons change, so do the cloud patterns. Clear skies and scattered cirrus clouds become more common in spring, offering a respite from the overcast conditions of winter.

Forecasting Cloud Cover in San Francisco

Predicting cloud cover in San Francisco can be challenging due to the city’s complex microclimates and the influence of the Pacific Ocean. While general weather forecasts provide an estimation of cloud cover, they often fail to capture the nuances of local variations. For a more accurate assessment, residents and visitors rely on real-time observations and short-term forecasts. The National Weather Service provides regular updates on cloud cover and visibility, allowing individuals to plan their activities accordingly. Additionally, local news broadcasts and weather apps offer localized forecasts that take into account the unique characteristics of different neighborhoods. By staying informed about cloud cover, San Franciscans can make informed decisions about whether to carry an umbrella, dress warmly, or simply enjoy the ever-changing skyscape.

Types of Precipitation

In San Francisco, the wet season typically runs from November to April, with an average annual rainfall of approximately 22 inches (56 centimeters). The most common form of precipitation during this time is drizzle, with rain occurring more frequently in the winter months. During the drier months of May through October, fog is a prominent feature, especially along the coast.

Weather Patterns Influencing Precipitation

The precipitation patterns in San Francisco are heavily influenced by the city’s geographic location. The city lies on the western coast of the United States, where it is exposed to Pacific storm systems that move eastward across the ocean. As these storms approach the coast, they are forced to rise over the coastal mountains, which causes the air to cool and condense, leading to the formation of clouds and precipitation. Additionally, the cold waters of the Pacific Ocean create a stable atmosphere near the coast, which contributes to the formation of fog.

Rainfall Patterns

San Francisco’s climate is heavily influenced by its proximity to the Pacific Ocean. The city experiences a Mediterranean climate, characterized by mild, wet winters and warm, dry summers. Rainfall is concentrated during the winter months, typically from November to April. During this period, the city receives an average of 20 inches of rain. The wettest months are January and February, when rainfall can exceed 5 inches per month. Summer months, on the other hand, are typically dry, with average monthly rainfall below 1 inch.

Annual Rainfall Variability

San Francisco’s rainfall patterns exhibit significant interannual variability. The city has experienced years with exceptionally high rainfall, such as 1973 when over 40 inches of rain fell. Conversely, it has also experienced years with below-average rainfall, including 2014 when rainfall totaled less than 15 inches. This variability is attributed to factors such as El Niño and La Niña cycles, which affect precipitation patterns across the Pacific Ocean. El Niño years typically bring above-average rainfall to San Francisco, while La Niña years result in below-average rainfall.

Historical and Recent Occurrences

Snowfall in San Francisco is a rare and unusual occurrence. Throughout its history, the city has experienced only a handful of significant snowfalls. One notable event occurred in 1856, when approximately 2 inches of snow blanketed the city, causing widespread disruption. Similarly, in 1976, San Francisco received a light dusting of snow, accumulating to about half an inch. However, these snowfall events are極度rare, and the city typically experiences warm, mild winters with little to no precipitation.

Climate Conditions

The rarity of snowfall in San Francisco can be attributed to the city’s unique geographic and climatic conditions. San Francisco is situated on a peninsula, surrounded by the Pacific Ocean on three sides. The city’s close proximity to large bodies of water moderates its climate, resulting in relatively stable temperatures throughout the year. Additionally, the prevailing winds in the area typically carry warm, moist air from the ocean, further preventing the formation of snow-producing conditions. The combination of these factors makes snowfall in San Francisco an uncommon meteorological phenomenon.

Climate and Weather:

San Francisco enjoys a temperate Mediterranean climate, characterized by warm, dry summers and mild, wet winters. The sun shines an average of 267 days per year, making it one of the sunniest cities in the United States. The summer months (June to September) are typically clear and comfortable, with average temperatures ranging from 58 to 77 degrees Fahrenheit (14 to 25 degrees Celsius). The winter months (December to March) are mild and rainy, with average temperatures ranging from 45 to 59 degrees Fahrenheit (7 to 15 degrees Celsius). The city receives an average of 22 inches (56 cm) of rainfall annually, most of which falls during the winter months.

Impact on Tourism and Outdoor Activities:

San Francisco’s sunny weather attracts numerous tourists and outdoor enthusiasts year-round. The city’s iconic landmarks, such as the Golden Gate Bridge and Alcatraz, are best experienced on clear, sunny days. The coastline and beaches, including Ocean Beach and Crissy Field, offer opportunities for swimming, sunbathing, and other recreational activities. The mild winter weather allows for outdoor exploration, including hiking in the nearby Muir Woods National Monument and visiting the Presidio National Park. Various parks and gardens, such as the Golden Gate Park and the Japanese Tea Garden, provide ample green spaces for relaxation and picnics in the sun.

Moonrise and Moonset Times

The moon’s position and visibility in San Francisco vary throughout the month and year due to the Earth’s rotation and the moon’s orbital path. The time of moonrise and moonset changes daily, influencing the duration of nighttime and the availability of moonlight.

During the full moon phase, the moon rises around sunset and remains visible throughout the night. Conversely, during the new moon phase, the moon is not visible as it aligns with the sun on the opposite side of the Earth. Between these extremes, the moon’s rise and set times gradually shift, resulting in a range of moonlit nights with varying levels of illumination.

Seasonal Variation of Humidity

San Francisco’s proximity to the Pacific Ocean significantly influences its humidity levels, which vary widely throughout the year. During the summer months (June to September), the city experiences a marine layer that brings high humidity levels, typically ranging from 70% to 80%. This layer forms when warm, moist air from the ocean meets cold, dry air over land, creating a persistent fog bank that blankets the city.

In the winter months (December to February), the marine layer typically dissipates, leading to a decrease in humidity. On clear days, the humidity may drop below 50%, creating a drier and more comfortable environment. However, during periods of rain or storms, humidity can still rise, especially when the wind blows moisture from the ocean into the city.

Daily Wind Patterns

San Francisco’s iconic wind patterns are a defining characteristic of the city’s climate. The prevailing wind direction is from the west, driven by the Pacific high-pressure system. These westerly winds typically strengthen during the afternoon and evening, creating a cooling effect on the city. During the summer months, the wind speeds can reach up to 30 miles per hour (48 kilometers per hour), providing respite from the warm temperatures.

Seasonal Variations

The wind patterns in San Francisco vary seasonally. During the summer, the westerly winds are strongest, while the fall and spring months experience more variable wind patterns. In the winter, the wind speeds tend to be lower, with occasional periods of strong winds associated with storms passing through the region. The city’s unique geography, with its hills and the presence of the Golden Gate Bridge, creates localized wind patterns and can result in microclimates with different wind speeds and directions within the city.

Spring (March-May):

Spring in San Francisco is characterized by mild temperatures, vibrant colors, and fewer crowds compared to the summer months. The average temperature ranges from 50 to 70°F, making it ideal for exploring the city’s outdoor attractions. The parks and gardens come alive with blooming flowers, showcasing the city’s natural beauty. This season offers a pleasant balance between warm weather and tranquility, providing an excellent opportunity to enjoy the city’s iconic landmarks without the overwhelming throngs of tourists.

Fall (September-November):

Fall is another ideal time to visit San Francisco. The temperatures are generally mild, with an average range of 55 to 65°F. As the leaves turn vibrant shades of red, orange, and yellow, the city transforms into a picturesque autumn wonderland. This season is renowned for its crisp air and clear skies, providing stunning views of the Golden Gate Bridge and the surrounding hills. Fall is also a great time to attend cultural events such as the San Francisco Film Festival and the Hardly Strictly Bluegrass Festival.

Solar Energy Potential

San Francisco boasts significant solar energy potential due to its abundance of sunshine throughout the year. The city receives an average of over 280 days of sunshine annually, with an average daily solar radiation of 4.5 peak sun hours. This favorable solar resource makes it an ideal location for solar energy development.

Solar Energy Installations and Capacity

Despite its solar energy potential, San Francisco has a relatively low solar energy adoption rate compared to other cities in California. As of 2022, the city had installed approximately 100 megawatts (MW) of solar photovoltaic (PV) capacity, which accounts for only a small fraction of its total electricity demand. However, there is growing interest in solar energy development in the city, fueled by both environmental concerns and the desire for clean and renewable energy sources.

Topography and Elevation

San Francisco is renowned for its distinctive topography, characterized by rolling hills, steep slopes, and picturesque bays. The city is built upon a series of hills, including Twin Peaks, Nob Hill, and Potrero Hill, each offering panoramic city and bay views. The highest point within the city limits is Mount Davidson, at 928 feet above sea level, while the lowest point is the waterfront, at sea level. The varied topography has shaped the city’s urban landscape, leading to the development of iconic landmarks such as the Golden Gate Bridge, which spans San Francisco Bay and connects the city to Marin County.

Geographic Features

San Francisco Bay, a major geographic feature of the city, is a large natural harbor that provides a deepwater port and serves as a gateway to the Pacific Ocean. The bay is surrounded by the cities of San Francisco, Oakland, and Berkeley, and is connected to the ocean by the Golden Gate Strait. The city is also known for its unique microclimates, influenced by the surrounding hills, bay, and ocean currents. These microclimates can create a range of temperatures and conditions within different parts of the city, from foggy mornings to sunny afternoons. The city’s topography and geographic features have played a significant role in its history, development, and cultural identity.

San Francisco International Airport (SFO)

San Francisco International Airport (SFO) is the primary airport serving the San Francisco Bay Area and the closest airport to downtown San Francisco. It is located just 13 miles south of the city center and offers a wide range of domestic and international flights. SFO is a major hub for United Airlines and also provides service from other major airlines, including Alaska Airlines, American Airlines, Delta Air Lines, and Southwest Airlines. The airport features four terminals connected by an automated people mover system, making it easy to navigate. SFO also offers a variety of amenities, including shops, restaurants, and free Wi-Fi.

Oakland International Airport (OAK)

Oakland International Airport (OAK) is another option for travelers looking to fly in or out of San Francisco. It is located approximately 17 miles east of downtown San Francisco and offers both domestic and international flights. OAK is a smaller airport than SFO, but it still provides a good selection of flights to major destinations. The airport is served by several major airlines, including Southwest Airlines, Delta Air Lines, and Spirit Airlines. OAK features two terminals and offers a variety of amenities, including shops, restaurants, and free Wi-Fi.

Arts and Culture

San Francisco is a hub for the arts and culture, with a vibrant theater, music, and art scene. The city is home to world-renowned venues such as the San Francisco Symphony, the San Francisco Opera, and the American Conservatory Theater. The city’s museums are equally impressive, including the San Francisco Museum of Modern Art (SFMOMA), the de Young Museum, and the California Academy of Sciences. San Francisco also boasts a thriving underground music scene, with countless intimate venues showcasing local and international artists.

Historic Sites and Landmarks

San Francisco is steeped in history, with iconic landmarks that tell the story of the city’s past. The Golden Gate Bridge, a symbol of the city, spans the Golden Gate strait and offers breathtaking views. Alcatraz Island, once a notorious federal prison, now hosts a museum and tours that unveil its fascinating history. The Fisherman’s Wharf district is a popular tourist spot, known for its seafood restaurants, shops, and the historic Pier 39, home to a colony of playful sea lions. Other notable landmarks include the Painted Ladies Victorian houses, Lombard Street (the “most crooked street in the world”), and the Japanese Tea Garden in Golden Gate Park.