Climate
Winter in San Francisco is rainy
and mild, spring sunny and temperate, summer foggy and cool, and autumn sunny
and warm. The average minimum temperature is51 °F (11 °C), and the average
maximum is 63 °F
(17 °C).
The mean rainfall, almost all of which occurs between November and April, is
about 21 inches (533 mm). There is sunshine
during two-thirds of the possible daylight hours. The most characteristic feature
of the weather, however, is the summer fog, which lies low over the city until
midday, creating consternation among shivering tourists. This fog is a phenomenon
of temperature contrasts, created when warm, moist ocean air comes in contact
with cold water welling up from the ocean bottom along the coast.

Lombard Street