What to pack for your vacation to San Francisco mostly depends on what time of the year you're travelling in.San Francisco sees mostly mild weather year-round, so t-shirts, shorts and jeans are a safe bet. Packing a few sweaters might also be wise, as the nights can get a little chilly. You should also pack comfortable walking shoes, as that is one of the preferred ways of getting around the city. Sunscreen protects you from the sun's UV rays when you step outside.