Continental climate

Continental climates often have a significant annual variation in temperature (warm summers and cold winters). They tend to occur in the middle latitudes (40 to 55 north), within large landmasses where prevailing winds blow overland bringing some precipitation, and temperatures are not moderated by oceans. Continental climates occur mostly in the Northern Hemisphere due to the large landmasses found there. Most of northern and northeastern China, eastern and southeastern Europe, Western and north western Iran, central and southeastern Canada, and the central and northeastern United States have this type of climate. Continentality is a measure of the degree to which a region experiences this type of climate. In continental climates, precipitation tends to be moderate in amount, concentrated mostly in the warmer months. Only a few areas—in the mountains of the Pacific Northwest of North America and in Iran, northern Iraq, adjacent Turkey, Afghanistan, Pakistan, and Central Asia—show a winter maximum in precipitation. A portion of the annual precipitation falls as snowfall, and snow often remains on the ground for more than a month. Summers in continental climates can feature thunderstorms and frequent hot temperatures; however, summer weather is somewhat more stable than winter weather. Continental climates are considered as temperate climate varieties due to their location in the temperate zones, but are classified separately from other temperate climates in the Köppen climate classification system where they are identified by their first letter, a capital D. In the Trewartha climate classification, they are identified as Dc. Most such areas have Köppen climate classifications of Dfa, with hot summers (mean temperature of the warmest month above 22 °C/71.6 °F), or Dfb, with warm summers (mean temperature of the warmest month below 22 °C/71.6 °F). Dry-summer continental climates (Dsa and Dsb) exist in high altitude areas near Mediterranean climates (Csa/Csb).