THE CLIMATE OF THE REGION
The whole area under consideration can be divided into three main climatic regions, the Plains, the Plateau, and the Pacific border, and each of these may be subdivided into northern and southern districts (Fig. 9).
(after R. de C. Ward).
TEMPERATURE. The Plains have what is essentially a continental climate. They are cut off from the Pacific Ocean by a great mountain barrier and do not feel the influence of any large body of water.1 When compared with the east of the United States,____________________
|North||40°F.||0°-10°F.||65°-70°F.||105°-110°F.||-50° to -60°F.|
R. de C. Ward, Climates of the United States ( Ginn and Co. 1925), p. 433.