Sonoran << suh NOHR uhn >> Desert is the largest desert in North America. It covers approximately 120,000 square miles (310,000 square kilometers) in northwestern Mexico and the southwestern United States. Parts of the desert lie in the states of Baja California and Sonora in Mexico and Arizona and California in the United States. The desert contains many landforms, including basin and range formations (parallel mountain ranges with valleys between them); playas (flat, dry lake beds); arroyos (dry stream beds); deep river valleys; inactive volcanoes; and sandy beaches. It also has the largest system of sand dunes in North America.
Temperatures in the Sonoran Desert vary widely depending upon the time of day, season, and location. Although the average temperature is above 65 °F (18 °C), temperatures can drop below freezing in northern regions and exceed 120 °F (49 °C) in southern regions. The average annual rainfall is about 5 to 12 inches (13 to 30 centimeters). Because the desert has both summer and winter rainy seasons, it has a greater variety of plants and animals than any other desert in the world.
Several million people make their home in the Sonoran Desert. The largest cities in the desert include Mexicali, Baja California; Hermosillo, Sonora; and Phoenix and Tucson, Arizona.
