January 2023 warmest on record for New York City

(PRISM Climate Group/Oregon State University)

Punxsutawney Phil may have predicted six more weeks of winter, but portions of the Northeast experienced temperatures more reminiscent of springtime as early as last month.

January 2023 was the warmest on record for multiple cities across the Northeast, including New York City which saw an average temperature of 43.5 degrees Fahrenheit.

"That's a whopping 9.8 degrees above normal," AccuWeather Senior Meteorologist Bob Smerbeck said.

It's also warmer than the city's 1991-2020 average March temperature of 42.8 degrees.

January, on average, is the coldest month of the year for the city. Yet every day's average temperature last month was above normal at Central Park, where the city's official weather station is located, according to AccuWeather Senior Weather Editor Jesse Ferrell.

"That hasn't happened since records began 154 years ago," he added.

Smerbeck attributed the unusually warm weather in part to the behavior of the polar vortex, or the mass of cold air that is bound to polar regions by strong winds known as the polar jet stream. When these strong winds weaken, cold air can plunge southward. But when the winds hold strong, it promotes a more westerly flow in the jet stream across the U.S., making storms more likely to track to the west and north of the northeastern United Staes, leaving the region on the warm side of the storm, according to Smerbeck.

La Niña, or a patch of warm water in the Pacific Ocean, combined with warm waters in the western Atlantic and Gulf of Mexico also helped to set up a pattern over the winter where the jet stream dipped into the western U.S. before lifting back into Canada.


"It has been colder than average across much of the western US this winter, like a see-saw," he said. "The jet stream has dipped southward across the western U.S. and lifted to the north into eastern Canada and bypassed the Northeast for much of the winter."

New York City was not the only one along or near the I-95 corridor to see its warmest January on record. Others include Washington, D.C.; Allentown, Pennsylvania; Bridgeport, Connecticut; and Worchester, Massachusetts.

While temperatures in Philadelphia rose to 9.6 degrees above average for the month, the city only saw its second-warmest January on record.

Data from Climate Central, a nonprofit news organization run by scientists and science journalists, shows that Januarys in New York are growing warmer, leading to a change of 4.7 degrees since 1970. January is also the month with the fastest rate of warming in New York, according to the nonprofit.

In the last month, New York had one day and six nights when temperatures exceeded level 2 on the Climate Shift Index scale, which measures the strength of the climate fingerprint on daily temperatures. A CSI of 2 indicates that climate change had a strong effect on that day's temperature.

While the state of New York has not escaped winter's hold, enduring grueling rounds of lake-effect snow in late November followed by the deadly cross-country storm that struck near Christmas as a bomb cyclone, the Big Apple itself didn't see actual measurable snowfall until Feb. 1, 2023, when 0.4 of an inch fell.

This was the latest first measurable snowfall for the city since record keeping began there in 1869, breaking the previous record set on Jan. 29, 1973.

The city had previously received precipitation since winter's official start, even recording 120% of the normal amount for a total of 4.38 inches. However, this mostly came in the form of rainfall due to the unusually high temperatures.

"The lack of snowfall this season is not for a lack of storms," AccuWeather Senior Meteorologist Dave Dombek said at the start of February. "There have been precipitation events, [but the] temperatures were just too high for snow."

A visitor basks in the sunlight on the Bow Bridge in Central Park, Monday, Jan. 30, 2023, in the Manhattan borough of New York. Since the start of winter in December, there hasn't been any measurable snowfall in the city. The last time it took this long before snow lingered on the ground in the wintertime was 1973, when New Yorkers had to wait until Jan. 29. (AP Photo/John Minchillo)

There were a few moments when flakes could be falling over the city, but these were eventually determined to only be trace amounts of snowfall or less than 0.1 inch

From March 9, 2022, to Jan. 31, 2023 -- a stretch totaling 328 days -- there was no measurable snow in New York City. This was the Big Apple's second-longest stretch of days without measurable snow on record, second only to the one that ended on Dec. 15, 2020, and lasted 332 days.

Other cities along the I-95 corridor also saw a break in the snow drought on Feb. 1, including Philadelphia, Baltimore and Dulles, Virginia. However, the totals were just above trace amounts.

The Philadelphia International Airport measured 0.3 of an inch of snow, and pre-dawn snow at a National Weather Service office near Dulles Airport in Dulles, Virginia, totaled 0.4 of an inch. Only 0.2 of an inch was measured in Baltimore.

Following the drastically low temperatures at the start of February, AccuWeather forecasters say the Northeast will once again experience mild weather that could last at least into the middle of the month.

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