2018–19 North American winter

The 2018–19 North American winter was unusually cold within the Northern United States, with frigid temperatures being recorded within the middle of the season. Several notable events occurred, such as a rare snow in the Southeast in December, a strong cold wave and several major winter storms in the Midwest, and upper Northeast and much of Canada in late January and early February, record snowstorms in the Southwest in late February, deadly tornado outbreaks in the Southeast and a historic mid-April blizzard in the Midwest, but the most notable event of the winter was a record-breaking bomb cyclone that affected much of the Central United States and Canada in mid-March. Unlike previous winters, a developing weak El Niño was expected to influence weather patterns across North America. Overall, however, winter of 2018–19 was mild along the mid- and lower parts of the East Coast, the West Coast, and most of the southern Plains. Overall, the meteorological winter of 2018-19 became the wettest on record for the United States.

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 2018 occurred on December 21, and ends at the March equinox, which in 2019 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. Winter is often defined by meteorologists to be the three calendar months with the lowest average temperatures. Since both definitions span the calendar year, it is possible to have a winter storm in two different years.