Full moon calendar 2021: When to see the next full moon

The next full moon will occur on Saturday, Dec. 18 at 11:36 p.m. EST (0426 Dec. 19 GMT), but the moon will appear full the night before and after its peak to the casual stargazer. The December full moon is also known as the Cold Moon.

The full moon shows its face to Earth about once a month. Well, sort of. 

Most of the time, the full moon isn’t perfectly full. We always see the same side of the moon, but part of it is in shadow, due to the moon’s rotation. Only when the moon, Earth and the sun are perfectly aligned is the moon 100% full, and that alignment produces a lunar eclipse.