The 2016-17 North American Winter was one of the mildest winters in modern North American history. The meteorological winter ran from December 1, 2016 to February 29, 2017, and the astronomical winter ran from December 21 to March 21, 2017, but in most parts of the continent it did not feel like winter. Any significant snowfall was largely confined to the Rockies, Upper Midwest, and Great Lakes, and locations as far north as Boston, Massachusetts and even parts of Atlantic Canada did not have any measurable snowfall accumulation. There were a few nor'easters, but snow was confined to the interior, and rain or mixed precipitation fell along the coast. During the month of February, a highly unusual heat wave struck much of North America, bringing extreme heat to many areas and setting many records. The winter coincided with the El Niño, which was the most powerful El Niño event on record.
On October 8, 2016, the National Oceanic and Atmospheric Administration's Climate Prediction Center issued its U.S. Winter Outlook for the winter of 2016-17. The presence of the record-breaking 2015-17 El Niño event was expected to strongly influence conditions, with almost the entire nation expected to have well above-average temperature and well below-average precipitation. The CPC noted the possibility of many locations having record low snowfall, and locations as far north as Washington, D.C. and the Pacific Northwest possibly having no measurable snowfall over the course of the entire winter. Drought, which had already developed over the Western states and had expanded into parts of the Midwest, was expected to expand further into the Eastern states.
On October 17, Environment Canada released its Canadian forecast for the months of December, January, and February. Well above-average temperatures and well below-average snowfall were forecast for almost the entire nation, with the exception of a small part of the Canadian Arctic Islands that were expected to have slightly above-average temperatures and near-average snowfall. The outlook also noted the possibility of record low snowfall in many locations, and the possibility that in some locations along the West Coast of Canada not having any measurable snowfall over the course of the entire winter.