Across much of America and especially in the normally chilly north, the country went through the winter months without, well, winter.
In parka strongholds Burlington, Vermont, and Portland, Maine, the thermometer never plunged below zero. The state of Minnesota called the last three months “the lost winter,” warmer than its infamous “year without a winter” in 1877-1878. Michigan, where mosquitos were biting in February, offered disaster loans to businesses hit by a lack of snow. The Great Lakes set records for low winter ice, with Erie and Ontario “essentially ice-free.”
For a wide swath of the country from Colorado to New Jersey, and Texas to the Carolinas, spring leaves are arriving three to four weeks earlier than the 1991-2020 average, according to the National Phenology Network, which tracks the timing of plants, insects and other natural signs of the seasons.
“Long-term warming combined with El Nino conspired to make winter not show up in the U.S. this year,” said Yale Climate Connections meteorologist Jeff Masters, who co-founded the private firm Weather Underground. Masters said he was bitten by a mosquito in Michigan this year, which he called crazy.
On Friday, the National Oceanic and Atmospheric Administration confirmed that the winter of 2023-2024 was the warmest in nearly 130 years of record-keeping for the United States. The Lower 48 states averaged 37.6 degrees (3.1 degrees Celsius), which is 5.4 degrees (3 degrees Celsius) above average.
This is just the latest in a drumbeat of broken temperature records, national and global, that scientists say is mostly from human-caused climate change from the burning of coal, oil and gas.
And it was the warmest U.S. winter by a wide margin. The past three months were 0.82 degrees (0.46 degrees Celsius) warmer than the previous record set eight years ago, which “is a pretty good leap above the previous record,” said Karin Gleason, chief of monitoring at NOAA’s National Centers for Environmental Information.
Last month was only the third-warmest February on record. But Iowa blew past its warmest February by 2 degrees, while parts of Minnesota were 20 degrees warmer than average for all of February, Gleason said. On Feb. 11, Great Lakes ice cover hit a February record low of 2.7%.
A strong ridge of high pressure kept the eastern United States warm and dry, while California kept getting hit with atmospheric rivers, she said.
The European climate agency Copernicus earlier this week said it was the warmest winter globally, mostly due to climate change with an added boost from a natural El Nino, which alters weather worldwide and provides extra heat.
In the past 45 years, winter has warmed faster in the United States than it has worldwide, with the Lower 48 states’ winters now averaging 2.2 degrees (1.2 degree Celsius) warmer than in 1980, according to an analysis of NOAA data by The Associated Press.
That’s probably because land warms faster than ocean with much of the United States as land and most of the globe as ocean, Gleason said.
While it is still getting warmer in the United States, since 2000 the rate of extra warming has slowed a bit, NOAA data shows. Winter weather expert Judah Cohen of Atmospheric Environmental Research, a commercial firm outside Boston, blames Arctic Amplification, which is how climate change has made the Arctic warm three to four times more than the rest of the globe and seems to shift weather patterns further south.
