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. Only when the moon, Earth and the sun are perfectly aligned is the moon 100% full, and that alignment produces a lunar eclipse

And sometimes — once in a blue moon — the moon is full twice in a month (or four times in a season, depending on which definition you prefer). [The Moon: 10 Surprising Facts]

This month’s full moon occurs on Sunday, July 5 at 3:33 a.m. PDT, but the moon will appear full the night before and after its peak to the casual stargazer. July’s full moon is known as the Buck Moon, though it has many other nicknames by different cultures. 

Remember this night!