Preliminary data indicates that the United States has experienced its warmest winter on record. Ahead of official reports by NOAA later this month, initial data collected by AccuWeather meteorologists shows that the average temperature across the United States ranks number one for the warmest winter.

This estimated data is based on the temperature ranking for Dec. 1, 2023, through Feb. 29, 2024, compared to all winters since 1893. State-by-state, Minnesota, Wisconsin and Michigan have had their warmest meteorological winter on record.

Cities ranking number one for warmest winter include locations outside of those three states, including Des Moines, Iowa; Fargo, North Dakota; Sioux Falls, South Dakota; Burlington, Vermont; Caribou, Maine; and Albany, New York. These cities had average winter temperatures of 8 to 12 degrees Fahrenheit above the historical average.

Unlike last winter, when the western United States was colder than the historical average, every state in the contiguous U.S. had higher-than-average temperatures this winter.

The strong El Niño that officially developed last summer significantly contributed to a mild, snowless winter season for the northern Plains, Midwest and Great Lakes, AccuWeather Lead Long-Range Expert Paul Pastelok said.

"December started with a strong, dominant storm track from the Gulf Coast to the Northeast. With a lack of cold air, these systems produced mainly rain and very little snowpack in the U.S. and Canada. The lack of snowpack led to a lack of persistent cold weather. Airmasses diving south out of Canada warmed after moving over the iceless Great Lakes into the East," Pastelok explained.

It wasn't just the U.S. that was warm, though.

"There were not many areas of the globe that were consistently cold through the 3-month period, so there was nowhere to drag any persistent cold air into the weather patterns of North America," Pastelok added.

A stormy weather pattern during January ended the snow drought that had been longer than 700 days for most of the Interstate 95 corridor, including New York City, Washington, D.C. and Philadelphia, but little snow fell after that date. Cities in the Northeast struggled to get snowfall the rest of the winter, with nearly every station reporting a snowfall deficit for the season. This included favored lake-effect snow belt locations like Syracuse, New York, lacking 59.3 inches of snow compared to the historical average. Boston fell 28.9 inches below historical average snowfall, and New York City was 16.9 inches in deficit.

In addition to El Nino, climate change shares some blame.

"The historic warmth this winter, as accurately forecast by AccuWeather’s long-range expert team more accurately and ahead of the NWS and other sources, follows trends that have been observed in recent decades—resulting from a warming atmosphere driven by climate change and other factors," said Jon Porter, AccuWeather Chief Meteorologist.

Ice cover on the Great Lakes reached a winter minimum since records began in 1973 due to the absence of prolonged cold spells. The lack of ice on the Great Lakes and other lakes and ponds across the region has been detrimental to folks who regularly go ice fishing in the winter or pursue other outdoor winter sports. However, the widespread warm spells have helped to reduce heating bills for residents across the region.