Temperatures colder than 10° above zero are infrequent in New York. Since 1970 the average number per winter has been three (in the 21st century the average has fallen to two days.) Not surprisingly, two-thirds of Central Park's frigid readings have occurred in January. The sweet spot is between Jan. 16-22, with the peak day being January 18, which has had readings in the single digits nine times. The earliest date since 1970 for a single-digit reading has been Dec. 3, which occurred in 1976; the latest was on February 28, 2014.
Temperatures of zero or below have been reported just eleven times since 1970, with the coldest reading of 2° below zero occurring on three occasions: Jan. 17, 1977; Jan. 21, 1985; and Jan. 19, 1994. There has been just one sub-zero reading this century and it occurred during the mild winter of 2016, when the mercury dropped to -1° on Valentine's Day. Not only was it a record for the date, it was also the first below zero reading since 1994, the first to occur in February since 1963, and the latest date for a sub-zero reading since 1934. (Previous to 2016's reading, the coldest reading of the 20th century was +1°, which occurred twice in January 2004.)
There have been 14 winters with 10 or more lows in the single digits or colder. The last time it happened was in the winter of 1936. The greatest number of frigid days, 20, occurred during the winter of 1918. More recently, the winters of 2015, 1994 and 1979 have had the most days with lows colder than 10° - nine. Since 1970 the most consecutive winters to have a sub-zero reading is four, 1933 to 1936. And the most consecutive days with single digit temperatures is six, which happened between Feb. 9-14, 1979. By contrast, 29 winters (since 1870) have had no readings below 10 degrees, including seven of the past fifteen (through the winter of 2020 - which was one of those seven winters).
Just one day since 1970 has had a high temperature in the single digits. It occurred during the great Arctic outbreak of January 1985. On Jan. 21 the high reached only 9° (after an AM low of -2°). That reading was reached shortly before midnight. During the daytime hours the temperature hovered around 7°. This was the coldest high temperature for New York since Feb. 15, 1943 when the high that day was just 8° (and that was the second time that winter with a high of 8°; the first was on Dec. 20).
Finally, in this century there have been six extended Arctic outbreaks of note. Three were in consecutive years - January 2003, 2004 and 2005. The most recent, during the winter of 2018, featured the third longest streak of highs 32° or colder on record (14 days, two days fewer than 1961's lengthiest streak and one less than a streak during the winter of 1881).