1893-94.] THE CLIMATE OF ALBERTA. 51 



A comparison of these average temperatures, etc., with those of other 

 parts of the Dominion shews that with the exception of South and 

 Southwestern Ontario and British Columbia there is no portion of the 

 country where the spring opens as early as in Alberta. 



The mean temperature of Northeastern Ontario, deduced from obser- 

 vations at Lindsay, Ottawa and Rockliffe, gives a March mean of 20.7°, 

 with a mean maximum of 31.1°, and an April mean of 38.2^ with a mean 

 maximum of 49.0°, shewing that during both these months the weather 

 is colder in Northeastern Ontario than in Alberta. 



From May to November the temperature is lower in Alberta than in 

 any of the more settled parts of Ontario. The warmest month is July, 

 with a mean of 60.5° at Calgary and 58.8° at Edmonton, and a mean 

 maximum of 74.0° and 72.9° respectively. 



In some years frosts occur in early June, but by no means invariably. 

 There is no instance recorded of the temperature at either station touch- 

 ing the freezing point in July. In August there are a few instances of 

 frost, but it is uncommon. 



Usually it is well on in November before the temperature falls to zero 

 roughly speaking between the 15 th and 20th. 



The month of December shews much the same figures as those of 

 Northeastern Ontario, the mean at Calgary being 17.2^, with a mean 

 maximum of 27.4° against 17.7° in Northeastern Ontario, with a mean 

 maximum of 25.8°. The advantage is thus with Alberta. 



The total mean annual precipitation is 14.16 inches at Edmonton and 

 12.85 at Calgary ; of this the greater portion falls as rain between April, 

 and September, the amount being 9.81 inches at Calgary and 10.61 

 inches at Edmonton, or about ^J^/^ of the amount which falls in the 

 Northeastern Ontario district during that period. 



In Alberta there is a great deal of sunshine, the annual amount of 

 cloudiness being only about 70^ of the average amount at Toronto; 

 roughly speaking the average cloudiness during the fall and winter 

 months is ^2°/ and about 50% in summer, but in Alberta summer and 

 winter months shew about the same amount, and give a yearly average 



THE CHINOOK. 



During the winter months the normal atmospheric pressure conditions 

 are anticyclonic over the interior of the continent, while over the northern 

 portions of the Atlantic and Pacific oceans there is tolerabh' persistent 

 low pressure. This distribution of pressure gives prevailing north- 



