<Tr> <Td> </Td> <Td> This section does not cite any sources . Please help improve this section by adding citations to reliable sources . Unsourced material may be challenged and removed . (October 2014) (Learn how and when to remove this template message) </Td> </Tr> <P> The large Westerly winds from the oceans also bring moisture, and the northern parts of the state generally receive higher annual rainfall amounts than the south . California's mountain ranges influence the climate as well: moisture - laden air from the west cools as it ascends the mountains, dropping moisture; some of the rainiest parts of the state are west - facing mountain slopes . Northwestern California has a temperate climate with rainfall of 15 inches (380 mm) to 50 inches (1,300 mm) per year . Some areas of Coast Redwood forest receive over 100 inches (2,500 mm) of precipitation per year . </P> <P> The Central Valley has a wide range of precipitation . The northern parts of the Central Valley receive substantially greater precipitation from winter storms which sweep down from the Pacific Northwest, while the southernmost regions of the Central Valley are near desert - like because of a lack of precipitation . Parts of the Valley are occasionally filled with thick fog (known locally as "tule fog"). </P> <P> The high mountains, including the Sierra Nevada, the Cascade Range, and the Klamath Mountains, have a mountain climate with snow in winter and mild to moderate heat in summer . Ski resorts at Lake Tahoe, Mammoth Lakes, and Mount Shasta routinely receive over 10 feet (3.0 m) of snow in a season, and some years, substantially more--leading, for example, to annual ski races on the Fourth of July . </P>

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