If you gaze upward tonight, you'll see the first of two full moon phases for the month of December.
The first full moon, happening tonight, is known as the "Full Cold Moon" marking the month of December which typically ushers in the cold weather. The second full moon, on December 31st, was named the "Full Long Night Moon."
At the time of the second full moon, nights are at their longest and darkest. The term Long Night Moon is a doubly appropriate name because the midwinter night is indeed long and the moon is above the horizon a long time. The midwinter full moon takes a high trajectory across the sky because it is opposite to the low Sun. This is the second time the moon turns full in a calendar month, so it is also popularly known as a "Blue Moon." Full moons occur on average each 29.53 days (the length of the synodic month), or 12.3683 times per year; so months containing two full moons occur on average every 2.72 years, or every 2 years plus 8 or 9 months.
A full moon on New Year's Eve? Yikes!