Weather in New York City in December

A hard month. December is a hard month in New York City, and worth planning around. Highs sit at 6.9 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

December ranks 10 of 12 — near the bottom of New York City's year. September is the month that works, and the swing between the two is 52 points, which is a different holiday rather than a slightly better one.

The rain arrives in bursts — 5 of the 10 wet days are heavy ones. Mornings tend to hold; build the outdoor half of each day before lunch and keep the afternoon flexible. Layers, and a genuinely waterproof outer — at 6.9 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: 8 nights fall below freezing; the day barely swings — 4.8 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest December day reached 17.9 °C and the coldest night fell to -10.7 °C, and the wettest single day dropped 80 mm — roughly 60% of the month's rain in one day.

December is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest December on record still delivered 244 mm against 52 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 133 mm average is a reasonable planning figure, not a promise.

Wind sits around 18.1 km/h — a steady breeze rather than a nuisance, and welcome on the warmer days, and humidity runs at 82%, which at 6.9 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How December sits in the year

The month is on the way down: 5 °C cooler than November, with January dropping another 3.4 °C. The first week and the last are not the same trip.

Daylight in December

December sits at the dark end of New York City's year — 9.3 hours of daylight against 15.1 at midsummer, holding steady all month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

Sea temperature

The sea sits at about 11.8 °C in December — too cold to swim without a wetsuit. The sea peaks at 24.4 °C in August and bottoms out at 6.8 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Quiet. Few other visitors, cheaper rooms, and a real chance some seasonal operators are shut.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

December in New York City versus nearby

If New York City is one option among several, the nearby comparison is worth making. Philadelphia is close enough to be a coin toss — within a degree on temperature, the same number of rain days. Boston is the weaker option in December — 2.8 °C cooler, 1 day more rain.

So: December is a compromise. September is 46 points better and is what New York City is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in New York City

See all twelve months in New York City, or where else to go in December.