is the terrestrial biome with the lowest annual average temperatures, with mean annual temperature generally varying from . Extreme winter minimums in the northern taiga are typically lower than those of the tundra. There are taiga areas of eastern Siberia and interior Alaska-Yukon where the mean annual reaches down to , and the lowest reliably recorded temperatures in the Northern Hemisphere were recorded in the taiga of northeastern Russia. Taiga has a subarctic climate with very large temperature range between seasons. would be a typical winter day temperature and an average summer day, but the long, cold winter is the dominant feature. This climate is classified as Dfc, Dwc, Dsc, Dfd and Dwd in the Köppen climate classification scheme, meaning that the short summers (24 h average or more), although generally warm and humid, only last 1–3 months, while winters, with average temperatures below freezing, last 5–7 months. In Siberian taiga the average temperature of the coldest month is between and . There are also some much smaller areas grading towards the oceanic Cfc climate with milder winters, whilst the extreme south and (in Eurasia) west of the taiga reaches into humid continental climates (Dfb, Dwb) with longer summers. According to some sources, the boreal forest grades into a temperate mixed forest when mean annual temperature reaches about . Discontinuous permafrost is found in areas with mean annual temperature below freezing, whilst in the Dfd and Dwd climate zones continuous permafrost occurs and restricts growth to very shallow-rooted trees like Siberian larch. Growing season The growing season, when the vegetation in the taiga comes alive, is usually slightly longer than the climatic definition of summer as the plants of the boreal biome have a lower temperature threshold to trigger growth than other plants. Some sources claim 130 days growing season as typical for the taiga. In Canada and Scandinavia, the growing season is often estimated by using the period of the year when the 24-hour average temperature is or more. For the Taiga Plains in Canada, growing season varies from 80 to 150 days, and in the Taiga Shield from 100 to 140 days. Other sources define growing season by frost-free days. Data for locations in southwest Yukon gives 80–120 frost-free days. The closed canopy boreal forest in Kenozersky National Park near Plesetsk, Arkhangelsk Province, Russia, on average has 108 frost-free days. The longest growing season is found in the