Climate of California

The climate of California varies widely from desert to alpine depending on latitude, elevation and how close the area is to the coast. Most of the coastal and southern parts of the state have a Mediterranean climate with somewhat rainy winters and dry summers. The deserts in the south of the state have very hot summers and mild winters. Parts of the south have a semi-arid/steppe climate, for example San Diego.
According to the National Oceanic and Atmospheric Administration (NOAA) averages from 1981-2010, 
California is the 13th warmest state in the United States with the average annual temperature of 58.4 °F (14.7 °C) 
Temperature range.
Northwest California has rainy cool winters and dry summers with temperatures in the summers in the upper 60s to the upper 70s. The Central Valley has a semi-arid climate with temperatures in the winter sometimes at nights fall below 30 °F (-1.1 °C) and at daytime rises above 80 °F (26.7 °C) with summers being from 80 °F (26.7 °C) to 100 °F (38 °C) at day. The desert areas in southern California has a hot and very dry climate with precipitation in some areas below 5 inches (127 mm) a year. Temperatures are mild in southern California's desert in the winter and temps can range from 60°F (15.5 °C) to 80°F (26.7 °C) at daytime with nights being chilly with temperatures ranging from 35°F (1.7 °C) to 50°F (10 °C). Temperatures are usually very hot during the day in desert places like Needles, San Bernardino and Palm Springs in the summer with daytime temperatures being from 105°F (40.5 °C) to 120°F (48°C) sometimes reaching above 120 °F (48 °C) and with nights being from 75°F (23.9 °C) to 90°F (32.2 °C). The hottest place in the world is in the desert of California, Death Valley. Death Valley once had a temperature of 134 °F (56.7 °C) on July 10, 1913 although some meteorologists dispute this temperature reading. The average annual temperature in Death Valley from 1981-2010 was 76.7 °F (24.8 °C) with an average July mean temperature of 101.8 °F (38.8 °C).