The cacti vary from diminutive cushions to the towering saguaro. Annuals are common, and if winter rains are sufficient, the desert is blanketed with wildflowers in March and April. Reptiles abound, including the colorful gila monster, as do birds found nowhere else in North America, such as trogons and several species of hummingbirds. The mighty Rio Grande River cuts through the heart of the desert. The landscape is mountainous, and the valley floors are high.
Winters are cold and summers are hot.
The Chihuahuan gets most of its precipitation in summer. Precipitation varies between 7 and 12 inches per year. Yuccas, agaves, cacti, and annuals like Zinnia grandiflora are common. The areas where precipitation is comparatively high support grasslands. The soils are high in calcium.