Quebec has three main climate regions. Southern and western Quebec, including most of the major population centres, have a humid continental climate (Köppen climate classification Dfb) with four distinct seasons having warm to occasionally hot and humid summers and often very cold and snowy winters. The main climatic influences are from western and northern Canada and move eastward, and from the southern and central United States that move northward. Because of the influence of both storm systems from the core of North America and the Atlantic Ocean, precipitation is abundant throughout the year, with most areas receiving more than 1000 mm(40 in) of precipitation, including over 300 centimetres (120 in) of snow in many areas. During the summer, severe weather patterns (such as tornadoes and severe thunderstorms) occur occasionally.

 

Most of central Quebec has a subarctic climate (Köppen Dfc). Winters are long, very cold, and snowy, and among the coldest in eastern Canada, while summers are warm but very short due to the higher latitude and the greater influence of Arctic air masses. Precipitation is also somewhat less than farther south, except at some of the higher elevations.

 

The northern regions of Quebec have an arctic climate (Köppen ET), with very cold winters and short, much cooler summers. The primary influences in this region are the Arctic Ocean currents (such as the Labrador Current) and continental air masses from the High Arctic.