Canadians climate is characterized by its diversity, as temperature and precipitation differ from region to region and from season to season. Factors influencing Canada's climate: 1) Latitude (extension from South to North) Since Canada's extension from south to north is 40*, the country is situated in 3 climatic zones: - the temperate zone (southern parts up to latitude approximately 60* North) - the subarctic zone (covers the parts of the country between latitude 60* North and the Arctic circle) - the arctic zone (includes territories, lying beyond the arctic circle) 2) Flow of air masses The usual air flow is from west to east. In winter it is disrupted by arctic air which moves down from the Arctic and is cold and dry. In summer the western air flow is disrupted by warm tropical air, moving from the southeast. This movement of air masses together with the countries position between the Oceans account for fact that there are several types of of climate within one climatic zone - the coastal parts (western and eastern) enjoy the maritime climate with abundant precipitation - the central interior parts enjoy the continental climate, which is characterized by great seasonal fluctuations in temperature and by a lesser amount of rainfall throughout the year. 3) The relief (the effect of mountain ranges, plains and bodies of water) The Cordilleran mountain system blocks the warm moist Pacific air from the interior plains of the Great Plains (the Prairie Provinces). The moist air is forced to rise over the mountains, it cools as it rises and falls on the western slopes in heavy amounts of precipitation, as rain in lower altitudes and snow at higher ones. On the lowland side of the mountains a rain-shadow effect is created. The valleys between the mountain ranges and the Great Plains lying further east receive much less precipitation. The rainfall is not sufficient and farmers have to irrigate their crops. Average winter and summer high temperatures across Canada vary depending on the location. Winters can be harsh in many regions of the country, particularly in the interior and Prairie provinces which experience a continental climatewhere daily average temperatures are near −15 but can drop below −40 °C (−40 °F) with severe wind chills. In non-coastal regions, snow can cover the ground almost six months of the year (more in the north). Coastal British Columbia is an exception and enjoys a temperate climate with a mild and rainy winter. On the east and west coast, average high temperatures are generally in the low 20s °C (70s °F), while between the coasts the average summer high temperature ranges from 25 to 30 °C (75 to 85 °F) with occasional extreme heat in some interior locations exceeding 40 °C (104 °F). According to its climate, Canada can be divided in to 5 regions: 1) The West Coast (the coast of British Columbia) - a temperate maritime West-Coast climate [the most temperate climate in Canada].
2) The Prairies (the Great Planes: Alberta. Saskatchewan, Manitoba) - a temperate continental climate [wind erosions, drought, thunderstorms, hailstorms, early autumn frosts, Chinook] 3) The Great Lakes (St. Lawrence region) - a temperate continental climate 4) Atlantic Canada - a temperate monsoon climate [rugged and variable] 5) The North - a subarctic and arctic climate [permafrost]
Inland Waters.
Canada holds vast reserves of water: its rivers discharge nearly 9% of the world's renewable water supply, it contains a quarter of the world's wetlands, and it has the third largest amount of glaciers (after Antarctica and Greenland). Because of extensive glaciations, Canada hosts more than two million lakes: of those that are entirely within Canada, more than 31,000 are between 3 and 100 square kilometers (1.2 & 38.6 mi²) in area, while 563 are larger than 100 km²
Rivers
The St. Lawrence (3050 km long) is Canada's most important river, for it provides a seaway for ships from the great lakes to the Atlantic Ocean. The Ottawa is its tributary. The longest Canadian river is the Mackenzie, which flows 4241 km through the Northwest Territories from the Great Slave Lake to the Beaufort Sea (the Arctic Ocean). A tributary of the Mackenzie is the South Nahanni River, which is home to Virginia Falls, a waterfall about twice as high as Niagara Falls. The Laird is another tributary of the Mackenzie. Mackenzie's length is counted together with the Peace. The Athabasca is another river of the arctic basin. Other large water recourses include the Yukon in the north and the Columbia in the Southeast, parts of these rivers flow through the US territory. The Frazer flows from the Rockies into Pacific. The Saskatchewan, the Nelsonandthe Churchill are the large river emptying into the Hudson Bay.
Lakes
There are some 2 million lakes in Canada. They cover about 7.6% of the Canadian landmass. Most of the lakes are glacial. The 4 Great lakes are the most visible results of the ice age in Ontario. The largest Lake Superior is the world's largest body of fresh water. The other Great Lakes in Canada are: Huron, Eerie and Ontario. They are traversed by the Canada-US border. Canada shares them with the US. The largest lake situated entirely in Canada is the Great Bear Lake in the Northwestern territories. Another large lake in the Northwestern territories is the Great Slave Lake. Saskatchewan (Lake Athabasca) and Manitoba (Winnipeg and Manitoba are the remains of the Lake Agassiz, which covered much of the province right after the ice age) are provinces of more than 100 000 lakes each.
