The climate of California varies widely from hot desert to alpine tundra, depending on latitude, elevation, and proximity to the Pacific Coast. California's coastal regions, the Sierra Nevada foothills, and much of the Central Valley have a Mediterranean climate, with warmer, drier weather in summer and cooler, wetter weather in winter. The influence of the ocean generally moderates temperature extremes, creating warmer winters and substantially cooler summers in coastal areas.

Temperature range

The cool offshore, enhanced by upwelling of cold sub-surface waters, often creates summer fog near the coast, creating a warm-summer Mediterranean climate (Köppen climate classification Csb). Farther inland, the climate becomes more continental, with some areas turning semi-arid (Köppen BSk), with colder winters and markedly hotter summers. Low-lying inland valleys, especially the Central Valley, have a hot-summer Mediterranean climate (Köppen Csa), with subtropical temperatures but a well-defined summer dry season and a foggy, rainy season in winter.

The temperature gradient between immediate coast and low-lying inland valleys in the south is about 7 °F (4 °C) in winter, the coast being warmer, and in summer roughly 20 °F (11 °C), the interior being warmer. For example, the average daily high in San Francisco in July and August is between 62 and 68 °F (17 and 20 °C),^[1][2] and in Walnut Creek, some 20 miles (32 km) inland, the average daily high in July and August is 84 °F (29 °C): a temperature gain of more than one degree (Fahrenheit) per mile.^[3] In Southern California, the temperature differences are approximately 4 °F in winter and 23 °F (2 °C and 13 °C) in summer. At the coast in Santa Monica, the average high in August is 75 °F (24 °C), while in Burbank, approximately 10 miles (16 km) inland, the average high in August is 95 °F (35 °C): a temperature gain of about two degrees Fahrenheit per mile.^[4]

During the cooler winter months (October–March), the Coachella Valley regularly has the warmest winter temperatures out of any place west of the Rocky Mountains. East Los Angeles, the Gateway Cities, and parts of the San Gabriel Valley average the warmest winter high temps (72 °F, 22 °C) in all of the western U.S., and Santa Monica averages the warmest winter lows (52 °F, 11 °C) in all of the western U.S. Palm Springs, a city in the Coachella Valley, averages high/low/mean temperatures of 75 °F/50 °F/63 °F, (24 °C/10 °C/17 °C) respectively during the period of cooler weather from November to April.^[5]

The extreme southwest, around San Diego, has a subtropical semi-arid or steppe climate (Koppen BSh) as winters are drier there.

The southeastern regions have a hot arid climate (Koppen BWh), similar to that of the Sahara Desert. In the northern portion of the Mojave Desert on the east side of the state is Death Valley, which has recorded temperatures among the highest in the world. It is common in the summer for temperatures in the valley to surpass 120 °F (49 °C). The highest reliably recorded temperature in the world,^[6][7] 134 °F (56.7 °C), was recorded in Death Valley on July 10, 1913. Temperatures of 130 °F (54 °C) or higher have been recorded as recently as 2005. The 24-hour average July temperature in Death Valley is 101.8 °F (38.8 °C) (1981–2010 NCDC Normals).

Alturas Bakersfield Bishop Bodie Death Valley Eureka Fresno Los Angeles Needles Redding Riverside Sacramento San Diego San Francisco San Jose Santa Rosa South Lake Tahoe class=notpageimage| Map of locations in the table below

Statewide records

The highest temperature ever recorded in California was 134 °F (57 °C) in Death Valley on July 10, 1913. This is also the highest temperature ever recorded on Earth. The lowest was −45 °F (−43 °C) in Boca on January 20, 1937.

Full statistics for selected cities