Welcome to the Desert Speakers website! Here you will learn a little about the Sonoran Desert. The Sonoran Desert covers an area that includes a large part Baja California and much of the state of Sonora in Mexico. In Arizona, the Sonoran desert covers about one third of the state, along the southern region. That means that there are distinct climate changes from the most southerly part of the desert to the most northerly. The Sonoran desert around Tucson is a sub tropical desert.