The month of December in New York City experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 51% throughout the month.
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In New York City, the chance of a wet day over the course of December is gradually decreasing, starting the month at 27% and ending it at 25%.
The average sliding 31-day rainfall during December in New York City is decreasing, starting the month at 3.6 inches, when it rarely exceeds 6.1 inches or falls below 1.4 inches, and ending the month at 2.7 inches, when it rarely exceeds 4.9 inches or falls below 0.8 inches.
The average sliding 31-day snowfall during December in New York City is rapidly increasing, starting the month at 1.4 inches, when it rarely exceeds 4.7 inches, and ending the month at 4.6 inches, when it rarely exceeds 13.1 inches or falls below 0.1 inches.
Over the course of December in New York City, the length of the day is essentially constant. The shortest day of the month is December 21, with 9 hours, 15 minutes of daylight and the longest day is December 1, with 9 hours, 29 minutes of daylight.
The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases.