Sonora is the county seat of Tuolumne County, California. As of the 2010 census, the city population was 4,903, up from 4,423 at the 2000 census. Sonora is the only incorporated community in Tuolumne County.
Sonora is located at 37°59′04″N 120°22′54″W / 37.984361°N 120.381767°W / 37.984361; -120.381767, around the intersection of California State Highways 49 and 108 The altitude is 1,825 feet (556 m). According to the United States Census Bureau, the city has a total area of 3.1 square miles (8.0 km²), 99.55% of it land and 0.45% of it water.
Sonora has cool, wet winters and hot, mostly dry summers. Average January temperatures are a maximum of 54.5 °F (12.5 °C) and a minimum of 33.5 °F (0.8 °C). Average July temperatures are a maximum of 94.6 °F (34.8 °C) and a minimum of 58.8 °F (14.9 °C). There are an average of 75.5 days annually with highs of 90 °F (32 °C) or higher and an average of 52.2 days annually with lows of 32 °F (0 °C) or lower. The record high temperature was 113 °F (45 °C) on June 22, 1961, and July 15, 1972. The record low temperature was 8 °F (−13 °C) on December 9, 1972.