Global weather activity of 2006 profiles the major worldwide weather events, including blizzards, ice storms, tropical cyclones, tornadoes, and other weather events, from January 1, 2006, to December 31, 2006. Winter storms are events in which the dominant varieties of precipitation are forms that only occur at cold temperatures, such as snow or sleet, or a rainstorm where ground temperatures are cold enough to allow ice to form (i.e. freezing rain). It may be marked by strong wind, thunder and lightning (a thunderstorm), heavy precipitation, such as ice (ice storm), or wind transporting some substance through the atmosphere (as in a dust storm, snowstorm, hailstorm, etc.). Other major non winter events such as large dust storms, Hurricanes, cyclones, tornados, gales, flooding and rainstorms are also caused by such phenomena to a lesser or greater existent.
Very rarely, well-defined winter storms may form during the summer, though it would usually have to be an abnormally cold summer, such as the Summer of 1816 in the Northeastern United States. In many locations in the Northern Hemisphere, the most powerful winter storms usually occur in March and, in regions where temperatures are cold enough, April.