MONTHLY RAINFALLS 39 



"The Pacific Type. — This type is found in all 

 of the territory west of the Cascade and Sierra Nevada 

 ranges, and also obtains in a fringe of country to the 

 eastward of the mountain summits. The distinguish- 

 ing characteristic of the Pacific type is a wet season, 

 extending from October to March, and a practically 

 rainless summer, except in northern California and 

 parts of Oregon and Washington. About half of 

 the yearly precipitation comes in the months of 

 December, January, and February, the remaining 

 half being distributed throughout the seven months 

 — September, October, November, March, April, 

 May, and June." 



"Sub-Pacific Type. — The term 'Sub-Pacific' has 

 been given to that type of rainfall which obtains over 

 eastern Washington, Nevada, and Utah. The in- 

 fluences that control the precipitation of this 

 region are much similar to those that prevail west 

 of the Sierra Nevada and Cascade ranges. There 

 is not, however, as in the eastern type, a steady 

 diminution in the precipitation with the approach 

 of spring, but rather a culmination in the precipi- 

 tation." 



"Arizona Type. — The Arizona Type, so called 

 because it is more fully developed in that territory 

 than elsewhere, prevails over Arizona, New Mexico, 

 and a small portion of eastern Utah and Nevada. 

 This type differs from all others in the fact that 

 about 35 per cent of the rain falls in July and 



