What is the subarctic climate in Canada?

The subarctic climate is the climate zone covering most of northern Canada south of the Arctic tundra, characterised by very cold long winters, short cool summers, low precipitation, and significant temperature extremes between seasons. The subarctic zone covers roughly 40 per cent of Canada's land area, including most of Yukon, the Northwest Territories south of the tree line, northern British Columbia, northern Alberta, northern Saskatchewan, northern Manitoba, northern Ontario, central and northern Quebec, and most of Labrador. The principal vegetation is boreal forest in the south, transitioning to taiga (more open forest with extensive lichen and bog cover) in the north.

Subarctic temperatures show the greatest seasonal range of any Canadian climate zone. Mean January temperatures range from minus 18 to minus 32 degrees Celsius, with extreme lows below minus 40 degrees Celsius common across the entire zone and below minus 50 degrees Celsius possible at the northern margins. Summer mean July temperatures range from 12 to 18 degrees Celsius, with daytime highs in the low 20s common in the southern subarctic. Snag, Yukon set the all-time Canadian low temperature record of minus 63.0 degrees Celsius on February 3, 1947.

Annual precipitation in the subarctic is generally low (250 to 500 millimetres per year, mostly as snow), with most summer rainfall coming as thunderstorms. The cold dry air limits evaporation, so even modest precipitation sustains extensive forest and wetland cover. The growing season is short (90 to 130 days frost-free in the southern subarctic, 60 to 90 days at the northern margins) and limited by both cool summer temperatures and the late spring snow melt. Daylight varies dramatically: communities above the Arctic Circle experience 24-hour daylight in summer and 24-hour darkness in winter, while subarctic latitudes have 18 to 20 hours of summer daylight.

The subarctic climate is rapidly warming due to climate change. Annual mean temperatures across most of subarctic Canada have risen by 2 to 3 degrees Celsius since 1948, more than double the global average warming. Effects include earlier ice break-up on rivers and lakes, longer wildfire seasons, expanding shrub cover into tundra zones, permafrost thaw, declining caribou populations, expanded ranges of southern species (moose, white-tailed deer, coyote) into the subarctic, and increased frequency of extreme weather events. Communities including Old Crow (Yukon), Tuktoyaktuk, Pangnirtung, and Hopedale have documented significant infrastructure and food-security impacts. The federal Climate Change Preparedness in the North programme and Indigenous Climate Knowledge Initiatives support adaptation.