Alberta has a dry continental climate with warm summers and cold winters. The province is open to cold arctic weather systems from the north, which often produce extremely cold conditions in winter. As the fronts between the air masses shift north and south across Alberta, temperature can change rapidly. Arctic air masses in the winter produce extreme minimum temperatures varying from −54 °C (−65 °F) in northern Alberta to −46 °C (−51 °F) in southern Alberta. In the summer, continental air masses produce maximum temperatures from 32 °C (90 °F) in the mountains to 40 °C (104 °F) in southern Alberta.

 

Alberta extends for over 1,200 kilometres (750 mi) from north to south; its climate, therefore, varies considerably. Average temperatures in January range from −8 °C (18 °F) in the south to −24 °C (−11 °F) in the north, and in July from 24 °C (75 °F) in the south to 16 °C (61 °F) in the north. The climate is also influenced by the presence of the Rocky Mountains to the southwest, which disrupt the flow of the prevailing westerly winds and cause them to drop most of their moisture on the western slopes of the mountain ranges before reaching the province, casting a rain shadow over much of Alberta. The northerly location and isolation from the weather systems of the Pacific Ocean cause Alberta to have a dry climate with little moderation from the ocean. Annual precipitation ranges from 300 millimetres (12 in) in the southeast to 450 millimetres (18 in) in the north, except in the foothills of the Rocky Mountains where rainfall can reach 600 millimetres (24 in) annually.

In the summer, the average daytime temperatures range from around 21 °C (70 °F) in the Rocky Mountain valleys and far north to 27 °C (81 °F) in the dry prairie of the southeast. The northern and western parts of the province experience higher rainfall and lower evaporation rates caused by cooler summer temperatures. The south and east-central portions are prone to drought-like conditions sometimes persisting for several years, although even these areas can receive heavy precipitation. Alberta is a sunny province. Annual bright sunshine totals range between 1900 and 2500 hours per year. Northern Alberta receives about 18 hours of daylight in the summer.

 

In southwestern Alberta, the cold winters are frequently interrupted by warm, dry chinook winds blowing from the mountains, which can propel temperatures upward from frigid conditions to well above the freezing point in a very short period. During one chinook recorded at Pincher Creek, temperatures soared from −18.9 °C (−2.0 °F) to 3.3 °C (38 °F) in one hour. The region around Lethbridge has the most chinooks, averaging 30 to 35 chinook days per year, while Calgary has a white Christmas only 59% of the time as a result of these winds.

Northern Alberta is mostly covered by boreal forest and has a subarctic climate. The agricultural area of southern Alberta have a semi-arid steppe climate because the annual precipitation is less than the water that evaporates or is used by plants. The southeastern corner of Alberta, part of the Palliser Triangle, experiences greater summer heat and lower rainfall than the rest of the province, and as a result suffers frequent crop yield problems and occasional severe droughts. Western Alberta is protected by the mountains and enjoys the mild temperatures brought by winter chinook winds. Central and parts of northwestern Alberta in the Peace River region are largely aspen parkland, a biome transitional between prairie to the south and boreal forest to the north.

 

After Southern Ontario, Central Alberta is the most likely region in Canada to experience tornadoes. Thunderstorms, some of them severe, are frequent in the summer, especially in central and southern Alberta. The region surrounding the Calgary-Edmonton Corridor is notable for having the highest frequency of hail in Canada, which is caused by orographic lifting from the nearby Rocky Mountains, enhancing the updraft/downdraft cycle necessary for the formation of hail.

 

 

Major cities in Alberta