Laguna Mountains are located in the eastern part of San Diego County. They range northwest to southeast for approximately 20 miles and peak at Cuyapaipe Mountain (6,378 feet). These mountains extend northwest about 35 mi (56 km) from the Mexican border at the Sierra de Juárez. The Sonora Desert lies to the east and the Santa Rosa Mountains are to the northwest. Climate As with the Transverse Ranges, areas along the coast tend to have less temperature variation than do inland areas. The Peninsular Ranges also form a rain shadow on the Colorado Desert region of California and on much of the larger Sonora Desert. The ranges are affected by the marine layer that provides cooling temperatures and fog, and rainfall varies seasonally with tropical storm activity. References Geography of California