A humid continental climate is a climatic region defined by Russo-German climatologist Wladimir Köppen in 1900. A place with a humid continental climate has big seasonal temperature differences. It has warm to hot (and often humid) summers and cold (sometimes very cold in the northern areas) winters. Precipitation usually happens throughout the year. In a humid continental climate, the average temperature of the coldest month must be below (or ) and there must be at least four months whose average temperatures are at or above .