Our weather and climate analysis offers a detailed understanding of average weather patterns for locations across the globe. Derived from 26 years of historical simulated weather data from ECMWF, it provides valuable insights into typical weather conditions, including air temperature, humidity, precipitation, cloud cover and wind. It is important to note the data is not observational, but rather derived from climate reanalysis.
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United States > San Francisco, CA > Overview
Discover if upcoming months are expected to be warmer, colder, wetter, or drier than average
What is the best time to visit San Francisco to enjoy the optimal weather conditions?
This quick reference weather table contains a summary of the annual climate trends in San Francisco. It contains key metrics, including average monthly high & low temperatures, rainfall, humidity and UV index. The data is presented on a monthly basis, allowing you to see how each these weather components change throughout the year.
San Francisco's long-term climate patterns earn these Weather Badges.
Explore the most extreme weather events in San Francisco over the past 26 years, including record highs and lows for temperatures, rainfall, and wind speeds. This data is sourced from the latest ERA5 reanalysis model spanning 2000 to 2025.
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Use our Climate Finder to search locations by their temperature and humidity patterns.
Weather guides, climate insights, and travel planning stories that talk about San Francisco.
San Francisco is characterized by a temperate Mediterranean climate, defined by remarkably stable temperatures and a lack of extreme heat or cold. WeatherBox data shows that the city experiences moderate thermal variation, with the average daily high reaching only 19.6°C (67.3°F) during the warmest month. Unlike many North American locations, the thermal peak often arrives in September rather than mid-summer. The maritime influence prevents scorching conditions, as temperatures rarely exceed 23.3°C (73.9°F). Conversely, mild winters generally keep the thermometer above 5.3°C (41.5°F), ensuring that freezing events are exceptionally rare.
Rainfall patterns exhibit a stark seasonal divide, alternating between arid summers and a pronounced rainy season. According to WeatherBox, the driest month sees an average precipitation of just 3 mm (0 in), creating parched conditions from mid-summer through early autumn. In contrast, precipitation increases significantly during the winter months, with December averaging 116 mm (5 in) of rainfall. This seasonal shift correlates with sunshine availability; the city enjoys abundant solar exposure in July with an average of 344.0 hours of sun, dropping to 137.8 hours during the cloudier, wetter winter solstice period.
The city's atmospheric profile is heavily influenced by its coastal position, with prevailing winds blowing from the W roughly 22.6 of the year. These breezes contribute to consistently pleasant humidity levels, which are rated as comfortable 97.2 of the time in the most agreeable month. While air temperatures remain moderate, solar intensity varies significantly, and the average peak UV Index is 8.6 during high summer. To gain a comprehensive understanding of these climatic patterns, explore the advanced weather charts and detailed averages available on WeatherBox.