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Current Weather & Forecast
In Depth Forecast
Climate
A quotation incorrectly attributed to Mark Twain says, "The coldest winter I ever spent was a summer in San Francisco." San Francisco benefits from California’s Mediterranean climate, characterized by mild wet winters and warm dry summers. However, surrounded on three sides by water, San Francisco has a climate strongly influenced by the cool currents of the Pacific Ocean which tends to moderate temperature swings and produce a remarkably mild climate with little seasonal temperature variation. Average summertime high temperatures in San Francisco peak at 70 °F (21 °C) and are 20 °F (9 °C) lower than in nearby inland locations like Livermore. The highest temperature ever recorded in San Francisco was 103 °F (39 °C) on June 14, 2000. Winters are mild, with daytime highs near 60 °F (15 °C). Lows almost never reach freezing temperatures, though the lowest temperature ever recorded in San Francisco was 27 °F (-3 °C) on December 11, 1932. May through September are quite dry, and rain is a common occurrence from November through March. Snow is extraordinarily rare, with only 10 instances recorded since 1852. The greatest snowfall on record was 3.7 inches (9.4 cm) in downtown San Francisco, and up to 7 inches (17.8 cm) elsewhere, on February 5, 1887. The last measurable snowfall in San Francisco was on February 5, 1976, when most of the city received an inch (2.5 cm) of snow.
The combination of cold ocean water and the high heat of the California mainland creates the city's characteristic fog that can cover the western half of the city all day during the spring and early summer. The fog is less pronounced in eastern neighborhoods, in the late summer, and during the fall, which are the warmest months of the year. Due to its sharp topography and maritime influences, San Francisco exhibits a multitude of distinct microclimates. The high hills in the geographic center of the city are responsible for a 20% variance in annual rainfall between different parts of the city. They also protect neighborhoods directly to their east from the foggy and cool conditions experienced in the Sunset District; for those who live on the eastern side of the city, San Francisco is sunnier, with an average of 160 clear days, and only 105 cloudy days per year.
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