The previous record for February 21 was 20 Celsius (68 degrees Farenheit) set in 1930, said Faye Morrone, meteorologist at the NWS's New York office.
Wednesday's temperature, taken in Central Park, was also a record high for the whole month of February, Morrone said.
The previous record highs, set recorded in 1930 and 1985, were of 23.88 degrees Celsius (75 Farenheit).
The unusually warm weather, which covers much of the northeastern United States and follows snow on Saturday, is not expected to last.
On Thursday "we will go back to temperatures much closer to normal," with a high of 7.2 Celsius (45 degrees Farenheit), Morrone said.