Average Annual Precipitation

he Sierra Nevada, like much of California, has a Mediterranean climate of warm, dry summers (driven by high pressure systems off the coast) and cool wet winters (governed primarily by the onshore movement of winter storm fronts down the Pacific Coast). Most precipitation falls between October and April, though the Sierra crest is subject to summer thunderstorms.

Precipitation ranges from less than 10 inches per year on the South Fork of the Kern River to over 80 inches per year in the mountains surrounding the North Fork of the Feather River. As is true for the Pacific Coast in general, precipitation is higher in the northern Sierra than in the southern end of the range. Even though the Sierra crest is over twice as high in the south, maximum precipitation is only half of that at the northern end of the range.

In the higher elevations (above about 5000 ft.), most precipitation occurs as snow (see Average Winter Snow Depth). In the lower elevations, most precipitation occurs as rain. In the lowest part of the foothills adjacent to the Central Valley, snow is extremely rare, and may not occur for decades.

The Sierra Nevada range acts as a giant water trap, wringing all the moisture from the Pacific storms as they move east. This is a boon to California agriculture, since the water from the Sierra flows into the Central Valley, but it also creates a vast rain shadow desert that stretches for five hundred miles to the east.

See also:

Adapted from Atlas of California, 1979.