2012–13 North American winter

The 2012–13 North American winter was the most active winter weather season by metric of the amount of storms rated on the Regional Snowfall Index (RSI), with a record-breaking 21 storms being rated on the scale. The season started out somewhat early, as the remnants of Hurricane Sandy brought heavy snow to the mountains of West Virginia in late October. Later, a strong nor'easter affected the weary Northeastern United States, hampering storm recovery efforts and dropping several inches of snow. The rest of the winter featured several other notable events, such as a Christmas winter storm that affected most of the Eastern United States, and the most notable event occurring in early February, when a powerful blizzard struck the Northeast and brought record snow to some areas. Overall, the majority of the continent, more specifically the central parts of the United States, experienced a persistently wintry and cold pattern that extended into the months of April and May, a theme that would be repeated the following winter on a larger and more widespread scale. During the winter, a weak El Nino was expected to influence weather conditions across the continent.

While there is no well-agreed-upon date used to indicate the start of winter in the Northern Hemisphere, there are two definitions of winter which may be used. Based on the astronomical definition, winter begins at the winter solstice, which in 2012 occurred late on December 21, and ends at the March equinox, which in 2013 occurred on March 20. Based on the meteorological definition, the first day of winter is December 1 and the last day February 28. Both definitions involve a period of approximately three months, with some variability. However, winter storms can occur outside of these limits, as shown by the very late winter storms that occurred throughout the months of April and even early May in parts of the central U.S.