California has about 35% of its total surface area covered by forests. California's diversity of pine species is unmatched by any other state. Though other states have a higher percentage of their land area covered by forests, in terms of total area, California contains more forestland than any other state except Alaska. Most of the forest is found in 2 places. First, in the northwestern part of the state and along the western slope of the Sierra Nevada. Smaller forests, mainly consisting of oaks, can be found along the coast ranges of California closer to the coast, and also in the foothills of the Sierra Nevada. Smaller areas of pine forests can be found in the San Gabriel and San Bernardino mountains of Southern California and also in the mountain areas of Central San Diego Country.

Deserts in California make up about 25% of the total surface area. In the south lie the Transverse Ranges and a large salt lake, the Salton Sea. The south-central desert is called the Mojave. To the northeast of the Mojave lies Death Valley, which contains the lowest, hottest point in North America. The lowest point of Death Valley and the peak of Mount Whitney are less than 200 miles apart. The hiking trek between the two points has been attempted, several times, most notably by Lee Bergthold. Indeed, almost all of southeastern California is arid, hot desert, with the Coachella Valley and Imperial Valley routinely experiencing extreme high temperatures during the summer.

Along the densely-populated and long California coast lie a number of major metropolitan areas, including those of San Jose-San Francisco-Oakland, Los Angeles-Long Beach, Santa Ana-Irvine-Anaheim, and San Diego. Climates near the Pacific Ocean are remarkably moderate compared with inland climates. Winter temperatures never reach freezing (snow is virtually unheard of) and summer temperatures rarely reach above the high 80's Fahrenheit (low 30's Celsius).

California is famous for earthquakes due to the presence of a number of faults, in particular the San Andreas Fault. While powerful earthquakes in the United States have occurred in other states such as Alaska, Washington, Oregon, and the Midwestern state of Missouri, (along the New Madrid fault), people are more aware of California's earthquakes due to their frequency and tendency to strike in highly populated areas. Some people believe that a huge, inevitable earthquake will result in the splitting of coastal California from the continent, either to sink into the ocean or form a new island. Notable movies in which the possible destruction of much of California by an earthquake include the titles Earthquake, A View to a Kill, Escape from L.A. and Superman.