Trails Across America. Fulcrum Publishing, Golden, Colorado. 1996. Cordes, Kathleen Ann. America's National Historic Trails. University of Oklahoma Press, Norman.
Temperatures are extremely high, largely precluding midday active recreation.
Winters are mild and ideal for all types of outdoor recreation. Rainfall is low, generally occurring in December, January, and February. In the coastal California and San Francisco Bay Area portions of the route, winters are mostly frost-free and summers mild. Outdoor recreation is a year-round possibility. The major part of these areas rainfall comes in the winter and early spring.