Places with a subarctic climate (also called boreal climate) have long, usually very cold winters, and short, warm summers. It is found on large landmasses, away from oceans, usually at latitudes from 50° to 70°N. Because there are no large landmasses at such latitudes, it is only found in the Southern Hemisphere at high altitudes (heights) in the Andes and the mountains of Australia and New Zealand's South Island. These climates are in groups Dfc, Dwc, Dfd and Dwd in the Köppen climate classification
This type of climate has very big changes in temperature throughout the year. In winter, temperatures can drop to -40 °C (also -40 °F) and in summer, the temperature may go above 30 °C (86 °F). But the summers are short; subarctic climates have no more than three months of the year (but at least one month) and must have a 24-hour average temperature of at least 10 °C (50 °F). The subarctic climate is part of the continental climate. The subarctic climate is found in the these places:
- Much of Siberia
- The northern half of Scandinavia (milder winters in coastal areas)
- Most of Alaska
- Much of Canada from about 50°N to the tree line, including:
With 5–7 months in a row where the average temperature is below freezing, all water in the soil and subsoil freezes several feet deep. Summer warmth is not enough to thaw (unfreeze) more than a few feet on the top of the soil, so there is a lot of permafrost (soil that is frozen forever). When the ice melts in the summer, 2 to 14 ft (0.6 to 4 m) of soil can thaw, depending on the latitude and the type of soil. Some subarctic climates near oceans (such as southern Alaska and the northern edge of Europe), have milder winters and no permafrost, so people can farm there.
Summer is very short; it has about about 45 to 100 days at most, and in a lot of places, the temperatures can go below freezing (32 °F or 0 °C) at any time of the year, even in the summer. Vegetation (plants) in a subarctic climate usually has low diversity (only a few different types of plants grow), because only hardy (very tough) species can survive the long winters and make use of the short summers. Trees are mostly ferns and evergreen conifers, because few broadleaved (big leaves) trees can survive the very low temperatures in winter. This type of forest is also known as taiga. The word taiga can also be a name for the climate itself. A lot of plants grow in the taiga (even if there are only a few different kinds of plants), so the taiga (boreal) forest is the largest forest biome on the planet, with most of the forests in Russia and Canada.
Is it usually very hard to farm in subarctic climates, because the soil is infertile (it doesn't have the nutrients that many plants need to grow) and because of the many swamps and lakes that ice sheets make, and only very, very tough crops (plants that grow on a farm) can survive the short growing seasons. (Even with the short season, the long summer days at these latitudes do allow some farming.)
There is very little precipitation (rain, snow, sleet, or hail); no more than 15 to 20 inches over an entire year. Away from the coasts, precipitation only happens in warm months. This means that the precipitation can soak into the ground and make it very wet and muddy.
Close to the Earth's poles and the water around the poles, the warmest month has an average temperature of less than 10 °C (50 °F), and the subarctic climate turns into a tundra climate, which is even worse for trees.
Here are some places with tundra climates:
- Fairbanks, Alaska
- Whitehorse, Yukon
- Yellowknife, Northwest Territories
- Thompson, Manitoba
- Moosonee, Ontario
- Goose Bay, Newfoundland and Labrador
- Rovaniemi, Finland
- Kiruna, Sweden
- Arkhangelsk, Russia
- Irkutsk, Russia
- Chita, Russia
Some places in the climate group Dfd (a very, very cold subarctic climate) are: