San Diego is one of the top-ten best climates in the Farmers' Almanac and is one of the two best summer climates in America as scored by The Weather Channel. Under the Köppen–Geiger climate classification system, the San Diego area has been variously categorized as having either a semi-arid climate (BSh in the original classification and BSkn in modified Köppen classification) or a Mediterranean climate (Csa and Csb). San Diego's climate is characterized by warm, dry summers and mild winters with most of the annual precipitation falling between December and March. The city has a mild climate year-round, with an average of 201 days above 70 °F (21 °C) and low rainfall (9–13 inches [230–330 mm] annually). Dewpoints in the summer months range from 57.0 °F (13.9 °C) to 62.4 °F (16.9 °C).
When does San Francisco receive most of its precipitation?