They have been keeping weather temperature records in Central Park in New York City since 1872. Since that year there have a total of 58 days when the temperature in Central Park in New York City was below zero.
The all-time coldest day in New York City history occurred on February 9, 1934, when the temperature dipped to -15 degrees. A very cold day to be sure, but it can get a lot colder than that in most parts of New York State.
The coldest day ever in New York State was -52 degrees, which occurred on February 18, 1979 in Old Forge, New York. I've been to Old Forge countless times as my family has many relatives up in that neck of the woods of upstate New York. Winters in that area of the Adirondack foothills can be brutally bad.
Below Zero Weather Temperature Days in NYC by Month
December - 15 days
January - 22 days
February - 21 days
The coldest month of the year in New York City is January, when the average daily temperature is 33 degrees. The next coldest month of the year in NYC is February when the temperature averages 35.7 degrees, followed by December at 37.9, and March at 42.9 degrees.
Below Zero Weather Temperature Days in NYC by Temperature
-1 degree 15 times
-2 degrees 14 times
-3 degrees 10 times
-4 degrees six times
-5 degrees two times
-6 degrees six times
-7 degrees two times
-8 degrees once
-13 degrees once
-15 degrees once
For more see 100 Degree Weather Temperature Days in New York City