Climate of California - Temperature Range

Temperature Range

The cool California Current offshore, enhanced by upwelling of cold sub-surface waters, often creates summer fog near the coast, creating a moderate oceanic climate (Köppen climate classification Cfb) on the northern coast and a moderate Mediterranean climate (Köppen Csb) from about Cape Mendocino southward. Further 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 Mediterranean climate (Köppen Csa), with subtropical temperatures but a well-defined summer dry season and cool, foggy, rainy season.

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 25 °F (14 °C) (the interior being warmer). One exception is worth noting - during the cooler winter months (Oct-Mar) the Coachella Valley, in the far southeastern corner of the State, constantly has the warmest winter temperatures out of any place west of the Rocky Mountains. 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 form Nov. to Apr. The temperature difference is most dramatic nearer the coast. For example, the average daily high in San Francisco in July and August is 72 °F (22 °C), and in Walnut Creek, some 20 miles (32 km) inland, the average daily high in July and August is 90 °F (32 °C); a temperature gain of approximately one degree (Fahrenheit) per mile. In the south, the figures are approximately 4 °F and 23 °F (2 °C and 13 °C), respectively. At the Santa Monica coast, 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 90 °F (32 °C); a temperature gain over one degree per mile. The temperature gradient is most extreme between Santa Barbara and Death Valley, with temperatures between the two differing by 4 °F and 35 °F (2 °C and 20 °C) in the winter and summer. The extreme southwest, around San Diego, has a semi-arid warm steppe climate (Koppen BSh) as winters are drier there. In San Bernardino the winters get a low of 30 °F (−1 °C) and in the summers a high of 109 °F (43 °C), because of this the weather is considered temperate since it is about 70 miles (110 km) inland from the Pacific Ocean in Southern California.

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 is the hottest spot on the Western Hemisphere. It is common in the summer for temperatures in the valley to reach 120 °F (49 °C). The highest temperature in the Western Hemisphere, 134 °F (57 °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).

High and Low Average Temperatures in Various Cities in California expressed in Fahrenheit and (Celsius) degrees