Northeast winters getting milder, study says

Average temperatures for season have risen since ’70

PHILADELPHIA — No one says snow and cold spells are things of the past. But winters have warmed considerably since 1970 in the Northeast, according to data compiled by Climate Central, an organization of scientists and journalists that research and report on climate.

Overall, the group found that winter not only is warmer than it was 50 years ago, but it is warming faster than any other season in 38 states, including Pennsylvania and New Jersey.

In Philadelphia, Climate Central calculated that average winter temperatures have risen 4.8 degrees since 1970 and that the season has 19 more days with abovenormal temperatures.

Atlantic City, New Jersey, winters have warmed 4.3 degrees, with 14 more days above normal.

To derive its findings, Climate Central used data from the Applied Climate Information System for 242 U.S. weather stations.

It calculated average temperatures and days above normal in December, January and February 1969-70, and compared the same months through 2019-20. An abovenormal winter day was defined as one with an average temperature above the 1981-2010 normal.

Of the meteorological stations, 98% had an increase in average winter temperatures since 1970, with most warming 2 degrees or more.

Overall, average winter temperatures increased the most around the Great Lakes and Northeast region, as did the number of days with above-normal temperatures.

Sean Sublette, a meteorologist at Climate Central who lives in Bucks County, said the 50-year data show an undeniable warming in the Philadelphia region.

However, even going back 150 years, minimum winter temperatures were rising, though not as quickly. Still, the data indicate a steady upward trend over time, he said.

“All these minimums here are going up,” Sublette said. “There’s been no going back down. You start seeing a very consistent rise about 50 years ago.”

He noted that temperatures are still rising even though the sun is currently in a less active portion of its normal cycle. Periods of lower solar activity usually mean lower temperatures.

However, Sublette said, the temperature trend is still rising, which scientists attribute to climate change.

Warmer winters might be enjoyable for some, but they can have serious consequences for industries such as agriculture.

“Fruit trees,” Sublette said, “need to be chilled cold for a good part of the winter so they get those cues to come out of dormancy and produce flowers and fruit. If that doesn’t happen, they get all messed up.”

Further, he said, it’s also potentially damaging to plants when they flower prematurely in, say, a warm February, then refreeze in early March.

Although ski resorts such as those in the Poconos are trying to stay ahead by diversifying their offerings, it’s not true that warming always means less snow, Sublette said.

In fact, at times, warming can produce bigger snowfalls.

Sublette said the Northeast has had some big snows in the past decade because warming has yielded more energy in the atmosphere to feed storms. Rising temperatures can still remain below freezing, setting the stage for a big Nor’easter.

Attempts to address climate change have been stalled since 2017 when President Donald Trump took office, pulled the U.S. out of the Paris climate accord and spent the rest of his term rolling back more than 80 environmental regulations, according to the Harvard Law School. Other organizations list more than 100.

Some of those rollbacks were aimed at curbing emissions from carbon and methane, both of which are greenhouse gases, from power plants, fracking operations, and auto emissions.