As it orbits the Earth our Moon goes through phases and "full" is when the Earth is between the Sun and the Moon. Because it is fully illuminated by the Sun at this time, it looks like a "full" round disk from Earth. These are some of the different names people call the full Moon in December: Cold Moon, Oak Moon, Frost Moon, Long Night's Moon, or Moon Before Yule. Do you believe that the full Moon causes strange behavior among people and animals? Awooooooooo!