If you're dreaming of convertibles, Frisbee on the beach, and tank-topped evenings, change your reservations and head to Los Angeles. Contrary to California's sunshine-and-bikini image, San Francisco's weather is "mild" (to put it nicely) and can often be downright bone-chilling because of the wet, foggy air and cool winds -- it's nothing like that of Southern California. Summer, the most popular time to visit, is often characterized by damp, foggy days; cold, windy nights; and crowded tourist destinations. A good bet is to visit in spring or, better yet, autumn. Every September, right about the time San Franciscans mourn being cheated (or fogged) out of another summer, something wonderful happens: The thermometer rises, the skies clear, and the locals call in sick to work and head for the beach. It's what residents call "Indian summer." The city is also delightful during winter, when the opera and ballet seasons are in full swing; there are fewer tourists, many hotel prices are lower, and downtown bustles with holiday cheer.
Climate
San Francisco's temperate, marine climate usually means relatively mild weather year-round. In summer, chilling fog rolls in most mornings and evenings, and if temperatures top 70°F (21°C), the city is ready to throw a celebration. Even when autumn's heat occasionally stretches into the 80s (upper 20s Celsius) and 90s (lower 30s Celsius), you should still dress in layers, or by early evening you'll learn firsthand why sweatshirt sales are a great business at Fisherman's Wharf. In winter, the mercury seldom falls below freezing and snow is almost unheard of, but that doesn't mean you won't be whimpering if you forget your coat. Still, compared to most of the states' weather conditions, San Francisco's are consistently pleasant.
It's that beautifully fluffy, chilly, wet, heavy, sweeping fog that makes the city's weather so precarious. A rare combination of water, wind, and topography creates Northern California's summer fog bank. It lies off the coast, and rising air currents pull it in when the land heats up. Held back by coastal mountains along a 600-mile front, the low clouds seek out any passage they can find. The easiest access is the slot where the Pacific Ocean penetrates the continental wall -- the Golden Gate.
Travel Attire -- Even if it's sunny out, don't forget to bring a jacket; the weather can change almost instantly from sunny and warm to windy and cold in San Francisco.
