Although huge in terms of offerings, San Francisco is physically quite compact. It is located on a seven-by-seven mile (11 x 11km) square of land at the tip of a peninsula between the San Francisco Bay and the Pacific coast. It has a population of 812,000 which represents a small fraction of the entire Bay Area population of 7.1 million.
With a mild climate including cool, wet winters and dry summers, for the most part you can expect the high’s in the upper 50s, 60s or low 70s. It’s almost never warmer than 73, never colder than 50. The nights are chilly so carry a light jacket.