JS'ew York Sta pj- :; 1 



snow. This has always been a difficult problem and, even under 



the most approved methods, when high winds prevail and there is 

 much drifting, there is a considerable error. A study of the 



earlier records for the winter months indicates that, as a rule, the 

 amount? recorded from snow were prohahly somewhat less than 

 the tine readings. 



GENERAL CLIMATIC CONTROL 



The principal factors that determine the general climate of a 

 place or region are the following: latitude; elevation of the land 

 surface; proximity of large bodies of water; prevailing winds; 

 and the location of the place or region with respect to the path of 

 cyclonic and anticyclonic disturbances. 



The latitude determines the amount of heat energy, technically 

 called insolation, received from the sun ; elevation influences both 

 temperature and moisture; bodies of water moderate the extremes 

 of temperature within their influence; winds not only transport the 

 temperature conditions of the regions from which they come, but 

 are moisture carriers as well; and cyclonic and anticyclonic dis- 

 turbances are the principal causes of extremes of temperature, and, 

 for most regions, the chief factors in the amount and distribution 

 of precipitation. 



The climate of places or regions even in the same latitude differ 

 widely, although the amount of insolation received from the sun 

 at all places equally distant from the equator is exactly the same. 

 For example, the average annual range of temperature between 

 the warmest and coldest months for Xew York City (January, 30 

 degrees, and July, 74 degrees) is 44 degrees; while for Eureka, 

 ( ;ilifornia, the January average is 47 degrees, the July, 56 de- 

 crees and the range 9 degrees, although the latitude is practically 

 the same in both cases, and both have the same mean annual tem- 

 perature, 52 degrees. The explanation for this wide difference is 

 found in the prevailing winds, which are westerly in both cases. 

 The temperature of Eureka is dominated by the winds from the 

 Pacific Ocean, which are relatively warm in winter and cool in 

 summer, while that of New York City is influenced mainly by 

 winds from the interior, which are decidedly warm in summer 

 and cold in winter. 



