The winter that wasn’t: Climate change is transforming Maine’s coldest season

Maine is closing the books on one of the warmest and least snowy winters on record.

But it’s increasingly feeling like the new normal.

“Weather varies from one year to the next, but the long-term trend is clear: The winters are much warmer than they used to be,” said state climatologist Sean Birkel of University of Maine’s Climate Change Institute. “Our winters look and feel different: more rain, less snow, more bare ground, earlier ice outs.”

This winter’s weather, and the long-term warming trend, spells trouble for the snowmobile industry, the ice fishing derbies and dog sledding races, and drives up operational costs for Maine’s ski resorts. But it’s not all bad: Plowing and sanding expenses are down, as well as home heating demand.

The winter of 2023-24 had some notable extremes, even though it didn’t quite break any statewide records, Birkel said.

The average 2023-24 winter temperature in Maine, which climatologists define as running from December through February, was 24.3 degrees Fahrenheit, according to UMaine climate data – making it the second-warmest on record, falling just below 2016’s 24.4-degree average.

It’s now been nine years since the average winter temperature dipped below the 20th-century baseline.

It was so warm that precipitation almost always came in the form of rain, not snow, and what snow did fall did not linger for long, records show. The average snow depth, which climatologists measure in its melted form, was just 0.87 of an inch of water, making the snowpack the fifth-smallest on record. On average, an inch of meltwater equals 10 inches of light, fluffy snow.

Maine’s smallest snowpack was recorded in 1983, with 0.71 inches of meltwater, records show.

While climatological winter ends in February, Maine can feel wintry well into April, especially in the north and western mountain regions, Birkel said.

But this March has been very warm, too, with average daily temperatures through March 26 in Bangor, Caribou and Portland ranking seventh-, sixth- and ninth-warmest.

As Maine continues to warm, winter seasons are becoming shorter and summer is becoming longer, according to the Maine Climate Office. Warming faster than any other season, Maine’s winters are now two weeks shorter than they were in the early 1900s, data show.

These changes will only be amplified in the future. Climate models project Maine may be 2 to 4 degrees hotter by 2050 and up to 10 degrees hotter by 2100, depending on the effectiveness of global efforts to reduce greenhouse gas emissions.