Temperatures

The farther south, the less severe the winter chill. Thus, while in January the inhabitants of Yellowknife cope with an average temperature of –28^oC, Torontonians experience –7^oC. But it is in Canada's far west, more specifically in Victoria, British Columbia, that the winters are the mildest, with an average temperature of 3^oC in January. The entire coast of British Columbia enjoys a clement winter climate, since it is swept by westerly winds warmed over the Pacific. Since the cordillera stops these air masses from moving east, the Prairie provinces are subject to bitterly cold blizzards that sweep down onto the plains from the Arctic.

	Winter forest, Yellowknife, N.W.T. ©2003 ICN-RCI / Hemera

Only a small region in southern Alberta enjoys a few episodes of respite during the winter, thanks to a warm, dry wind from the Pacific that sometimes manages to find its way there. This wind is called the Chinook, meaning 'he who eats snow,' because it can make the temperature jump 25^oC in an hour. The moderating effect of the ocean is also felt on the East Coast, but to a lesser extent because of the west-to-east flow of air masses and the frigid Labrador Current along the Atlantic coast.

Toronto skyline, Ont. ©2003 ICN-RCI / Hemera

During the summer, air masses from the American southwest and the Gulf of Mexico exhale their hot breath onto the southern part of Canada. They bring especially hot summers to the Prairies, where nothing intervenes to temper their effects. Summer temperatures are lower on the coasts, which are cooled by ocean air. In Canada's North, there's a nip in the air all summer, since warm winds seldom visit such high latitudes.

The number of frost-free days, which provides a good idea of the growing season, is of prime importance for agriculture. Southwestern British Columbia, which has from 200 to 250 frost-free days, is definitely the most favoured region of Canada in this regard, but its arable land is limited. Thus the St. Lawrence and Great Lakes lowlands, whose southern part enjoys a frost-free period of 125 to 175 days, are known as the farming centre of Canada. Farmers in valleys on the Atlantic coast must cope with a somewhat shorter season, while those on the Prairies are clearly limited in their choice of crops, with a frost-free season of only 90 to 120 days.