Cold Moon

December's full moon, the Cold Moon, reaches peak illumination on Monday, December 13, 2027, at 11:09 a.m. EST (16:09 UTC). To the naked eye, the Moon looks full for about a day on either side of the peak. That makes the evenings of December 12 and December 13 the best nights to watch it rise.

Quick facts

Peak time by US time zone

The Moon is exactly full at one instant worldwide. Only the clock reading changes.

Times are calculated with the open-source astronomy-engine library. Other published sources may differ by about a minute because of rounding.

Is it a supermoon?

No. At full phase the Moon is about 368,131 km from Earth (center to center), not close enough to perigee (364,018 km) to qualify under the common definitions.

Best viewing tips

Watch the moonrise. In New York City, the Moon rises at about 3:21 p.m. on December 12 (sunset 4:28 p.m.) and at about 4:21 p.m. on December 13 (sunset 4:28 p.m.). Times for your city will differ, so check the Moonlix moonrise page for your location.

Find a clear eastern horizon. Near the horizon, the full moon often looks orange and unusually large. The color comes from Earth's atmosphere filtering out blue light. The size is the well-known Moon illusion, a trick of perception rather than a real change.

Where it sits in the sky. At its highest, this full moon is high in the sky for mid-northern US latitudes. The December full moon is usually one of the highest of the year. It is excellent for seeing lunar seas clearly, but bring warm layers for long nights outdoors.

Binoculars and cameras. Ordinary 7x50 or 10x50 binoculars show the dark lunar seas and the bright rays around the crater Tycho. For photos, use a tripod and a telephoto lens, shoot during blue hour just after sunset, and expose for the Moon. A good starting point is ISO 100, f/8 and 1/250 s.

Name origin and folklore

December brings the long, cold nights of early winter, and the Cold Moon name reflects them. Long Night Moon refers to the full moon closest to the winter solstice. Opposite the low winter Sun, it rides high across the sky and stays up for most of the night.

Other names recorded for this month's full moon include Long Night Moon, Oak Moon. Most full moon names popular in the US today were spread by the Old Farmer's Almanac and the Farmers' Almanac. Native nations had their own names, which varied by region and language, so no single list is "official."

What else is in the sky

The main meteor shower this month is the Geminids (around December 13–14). Check the Moon's phase on the peak night, because bright moonlight hides fainter meteors. The December solstice falls on December 21 at 9:42 p.m. EST. Use the December 2027 moon calendar to see every phase, and the daily moon phase pages for illumination on any date.