San Francisco weather is much maligned. The city, surrounded on three sides by water, is best known for the blankets of fog that roll in from the Bay, but that same Bay gives the area a mild, temperate climate with an average temperature of around 50 degrees. San Francisco weather is generally pleasant, but changeable. Enjoy the city with a jacket or umbrella stowed nearby.
The fog for which San Francisco is known is caused by the cool air rising from San Francisco Bay waters meeting the hot inland air from central California. The resulting fog gives the city its characteristic mysterious aura, but don't worry; it almost always burns off by noon.
Spring and Summer in San Francisco
Spring and summer in San Francisco tend to be cool. While inland California suffers through some of the hottest summer temperatures in the country, the Bay area stays cool, even cold at times. It was the famous 19th century author, Mark Twain who quipped that "the worst winter I ever spent was summer in San Francisco." Acturally, the average summer temperature range from 60 to 75 degrees, and evenings in the summer can be rather cool, with temperatures dipping to the low 40s, but never quite to the freezing point. One bright point: rain is rare in the summer in San Francisco.
Fall and Winter San Francisco Weather
Fall in San Francisco starts out gloriously with crisp sunny days and cool, but not freezing nights, ideal for curling up by a wood-burning fireplace. The Bay leaves put on a wonderful fall display with the cool evening helping to accent their vibrant red, orange, and yellow hues.
San Francisco weather in the winter season turns rainy, but snow is virtually never seen. The last measurable snowfall was in 1887!
San Francisco Bay and the Pacific Ocean held keep the San Francisco area insulated from extreme heat and cold. Less than an hour's drive inland, in Stockton, Modesto, and Sacramento, the heat soars near 100 degrees in the summer, while San Francisco remains in the 60s and 70s. In the winter, too, the inland communities experience more extreme temperatures, though rarely do they get more than a dusting of snow.
The Best Time to Visit San Francisco
Arguably, the best time to visit the Bay Area is in September and October. Typically, "Indian Summer" season in San Francisco, the sun shines, the air is crisp and often in the 70s, and the trees are starting to show their fall colors. Fall is also the grape harvest season, and a trip up to California's wine country is a must for any fall San Francisco vacation.
San Francisco residents delight in their mild climate and changeable weather. Since they experience all of the seasons, fashion enthusiasts can sport winter coats and sweaters as well as lightweight summer wear. They don't, however, have to deal with the extreme heat of Arizona or the extreme cold and snow of Buffalo. The well-informed San Francisco resident dresses in layers. That way they are prepared for every weather eventuality. In short, the "City by the Bay" has a unique climate all of its own. Enjoy it for its own merits.