San Francisco Bay Area in January

September and October deliver the Bay Area's best weather — warm, clear days with minimal fog. This is when locals actually wear shorts and the city feels most alive. April through June works too, though you'll battle more tourists and the occasional surprise rain shower. Summer brings the famous fog that blankets the city most afternoons. Mark Twain never actually said that thing about the coldest winter, but he should have. Pack layers — it can be 75°F in the Mission and 55°F in the Sunset simultaneously. Winter means rain but also fewer crowds and cheaper hotels. The holidays bring holiday markets to Union Square and surprisingly good storm watching from Ocean Beach. Just avoid the first week of October when Dreamforce takes over downtown and hotel prices triple.