CLIMATE 317 



These great extremes of annual temperature, and the sudden 

 changes of temperature and of humidity which accompany the 

 passage of cyclones and anticyclones, make the term ''temperate" 

 singularly inappropriate for the intermediate zones. 



The climates of the northern and southern intermediate zones 

 are very unlike. The difference is due chiefly to the greater extent 

 of land in the northern henisphere. The climate of most of the 

 southern zone is oceanic, while the climate of much of the northern 

 zone is continental. 



Compared with the corresponding zone of the northern hemi- 

 sphere, the cool summers are one of the striking features of the 

 intermediate zone of the southern hemisphere. Cloudiness and 

 humidity prevail, except in the lee of mountains. These charac- 

 teristics of the climate are not favorable for agriculture, and the 

 lands of the southern hemisphere in latitudes corresponding to those 

 of London and New York, are usually unproductive. This is be- 

 cause of the cool summers, rather than because of cold winters. 



Westerly winds prevail in the intermediate latitudes (p. 274), 

 and many features of the climate in these zones are determined by 

 them. The effect of these winds on the climate of the United 

 States has already been outlined (p. 279). Where they blow over 

 land which is warmer than the sea (lowlands in summer), they are 

 dry winds , because they take up moisture; but when they blow over 

 land which has a temperature lower than their own (most lands in 

 winter, and mountains at most times), some of their moisture is 

 condensed, and rain (or snow) falls. The windward slopes of high 

 mountains in these zones are therefore well supplied with moisture, 

 while plains to the lee of such mountains are generally dry. The prin- 

 ciples of this explanation may be applied to other lands in this zone. 



Middle latitudes do not depend entirely on the westerly winds 

 for their rainfall. Cyclones often furnish moisture (p. 287) where 

 the westerly winds would bring none. Thus east of the 98th 

 meridian in the United States the rainfall is generally enough for 

 farming, though not supplied by winds from the Pacific. 



The cyclone and the anticyclone are important factors in the 

 temperature, as well as the precipitation, of the intermediate zones. 

 They give us our greatest annual extremes of heat (during cyclones 



