A humid continental climate is a climatic region defined by Russo-German climatologist Wladimir Köppen in 1900, typified by four distinct seasons and large seasonal temperature differences, with warm to hot (and often humid) summers and cold (sometimes severely cold in the northern areas) winters. Precipitation is usually distributed throughout the year but often does have dry seasons. The definition of this climate regarding temperature is as follows: the mean temperature of the coldest month must be below or depending on the isotherm, and there must be at least four months whose mean temperatures are at or above . In addition, the location in question must not be semi-arid or arid. The cooler Dfb, Dwb, and Dsb subtypes are also known as hemiboreal climates. Humid continental climates are generally found between latitudes 40° N and 60° N, within the central and northeastern portions of North America, Europe, and Asia. They are rare and isolated in the Southern Hemisphere, due to the larger ocean area at that latitude, smaller land mass, and the consequent greater maritime moderation. In the Northern Hemisphere, some of the humid continental climates, typically in Hokkaido, Northern Honshu, Sakhalin island, northeastern mainland Europe, Scandinavia, Nova Scotia, and Newfoundland are closer to the sea and is heavily maritime-influenced and comparable to oceanic climates, with relatively cool summers and winters being just below the freezing mark (too cold for such a classification). More extreme and inland humid continental climates found in northeast China, southern Siberia, the Korean Peninsula (except for the southern region in South Korea) and the Canadian Prairies, where temperatures in the winter resemble those of subarctic climates but have warmer and longer summers. In east-central China, southern South Korea, the Great Lakes region of the American Midwest, New England, and southern parts of Central Canada the climate combines hotter summer maxima and colder winters than the marine-based variety and are less extreme than the most inland variety, with similarities to the adjacent humid subtropical climate but with colder winters which preclude such classifications. Definition Using the Köppen climate classification, a climate is classified as humid continental when the temperature of the coldest month is below or and there must be at least four months whose mean temperatures are at or above . These temperatures were not arbitrary. In Europe, the average temperature isotherm (line of equal temperature) was near the southern extent of winter snowpack. In the