It was down right balmy in New York City this December! With an average temperature of 50.8°F in Central Park, which is a staggering 13.3°F above average, it was the city’s warmest December on record. The previous record of 44.1°F was set in 2001.
Overall, we had thirty out of thirty-one days with high temperatures above average. Five of those days tied or broke daily high temperature records, including Christmas Eve when the mercury soared to a spring-like 72°F in Central Park. Overnight lows were also above average throughout the month. In fact, this was the first December on record that overnight temperatures did not fall below freezing at least once.
While a few warm days in December is not that uncommon, this extended pattern of sustained warmth was very unusual. Driven primarily by El Niño, a persistent ridge in the jet stream over the eastern US allowed warm southern air to flow further north than it normally would at this time of year.
Given this unseasonable warmth, it is not surprising that only a trace of snow was measured in Central Park this December. On average, NYC usually receives 4.8 inches of snow for the month. Rain, on the other hand, was plentiful. In fact, December marked the first time since June that we saw above average rainfall. In all, the city received 4.72 inches of rain, which is 0.72 inches above normal. The majority of this total fell during two separate heavy rain events, which seem to be getting more common. Nonetheless, according to the latest report (12/29) from the US Drought Monitor, the city remains in a moderate drought.