CLIMATE. 177 



valley is of great agricultural value, on which more than half the 

 population of Canada lives, 



3. Climate. 



It will easily be understood that the climate of Canada differs 

 considerably in the various parts of the country. These 

 differences are best illustrated by the rainfall. The high moun- 

 tains of the west intercept the rainbearing clouds from the Pacific 

 Ocean, producing, along the west coast, a strip of high rainfall up 

 to 100 inches. A somewhat diminished but still considerable 

 rainfall is experienced up to the watershed of the Rockies. After 

 passing that chain, the remaining clouds descend in their eastern 

 passage, and the rainfall diminishes considerably, so that Calgary, 

 in Alberta, shows a fall of only 16 inches, Regina, in Saskatchewan, 

 of 18 inches, and Winnipeg, in Manitoba, 20 inches. Proceeding 

 further east the rainfall increases again, the country coming under 

 the influence of easterly air currents, as well as under that of the 

 Lakes and of Hudson Bay. Thus, Toronto, in Ontario, has a fall 

 of 34 inches, Montreal, in Quebec, 41 inches, Charlottetown, in 

 Prince Edward Island, 42 inches, Fredericton, in New Brunswick, 

 44 inches, and Hahfax, in Nova Scotia, 55 inches. Precipita- 

 tions decrease, not only on proceeding from both coast lines 

 towards the interior, but also on going north. Over the greater 

 part of Canada much of the precipitation is in the form of 

 snow. 



Southern Canada lies within the cool temperate zone with 

 rather cold winters and hot summers. On going north the 

 temperature falls and the severity of the winters increases, until 

 vegetation disappears, so that three distinct zones may be 

 distinguished : — 



(1) The Temperate Zone, comprising (a) the eastern or Atlantic 



forest region, extending to the Great Lakes, (6) the central 

 drier region of prairies, and (c) the western or Pacific 

 forest region. 



(2) The Sub-arctic Zone, a continuous area of coniferous 



forests, less luxuriant than the forests of the temperate 

 zone, stretching obliquely across the entire continent. 



(3) The Arctic Zone, comprising mainly desolate stretches of 



treeless country known as " tundra." 



