Visit Phoenix to explore more than 33,000 acres of Sonoran Desert preserves, 7,300 acres of desert parks and 180 miles of trails. Parking areas for most preserve areas are open daily from 5 a.m. to 7 p.m. Check area pages for specific hours. All preserve trails (South Mountain, North Mountain, Piestewa Peak and the Sonoran Preserve) are open until 11 p.m. Hours for trails in desert parks (Camelback Mountain and Papago) vary.
Check out this video chronicle of hiking South Mountain Park to get a great picture of the wonders of the Phoenix desert preserve system.