The cold moon will turn full at 8:20 a.m. EST on Thursday, Dec. 4. It will look full the night before and the night after, but the best time to watch it rise in North America will be at moonrise during dusk on Friday, Dec. 5, when it will appear on the eastern horizon shortly after sunset.

According to EarthSky, December’s full moon can be known as the cold moon, the long nights moon, and the moon before yule, the latter of which is an old English name (yule means winter festival).

The cold moon is 2025’s third supermoon in a row. The moon’s orbital path around Earth is slightly elliptical, so each month, there’s a point when it’s farthest away (apogee) and closest (perigee). If a full moon coincides — or thereabouts — with the moon’s point of perigee, it will be closer to Earth and bigger in the night sky. That scenario is also known as a supermoon. The cold moon will be 100%-lit just 12 hours after its perigee.

A supermoon is defined as one that is 10% closer than the average distance. The moon’s average distance from Earth is 238,900 miles (384,472 kilometers). At 221,965 miles (357,218 kilometers), the cold moon will be the second-closest full moon of the year, so the second-biggest and brightest.

As well as being the earliest to rise of the year in the Northern Hemisphere, December’s cold moon is the highest-hanging full moon of the year. This happens because the full moon is opposite the sun, by definition, so it mirrors the sun’s position. With the solstice coming up on Dec. 21, the sun is at its lowest in the sky, so the full moon is therefore at its highest. In practice, that means it gets very high in the sky.

A full moon always looks at its best when it first appears above the eastern horizon during dusk. The sight is at its most dramatic when the moon rises shortly after sunset, which it does this month in North America, with the cold moon rising about 25 minutes after the sun goes down.