Full Thunder Moon

The Full Thunder Moon on July 18, 2008. (NASA/Sean Smith / July 3, 2012)

March's full moon arrives Wednesday morning, the first to fall after the vernal equinox.

It is the fourth full moon after the winter solstice, something that usually falls in April. This full moon is known by names including Grass Moon, Egg Moon, Growing Moon, Waking Moon and Pink Moon.

But if you ask sources like the Farmer's Almanac or Old Farmer's Almanac, it is the Full Worm Moon. In ancient times, the naming of full moons was dependent on where they fell relative to events like the winter solstice or vernal equinox, but modern usage sticks with the same moon name for any given month.

Whatever you call it, the moon reaches its fullest phase at 5:27 a.m. Wednesday, so look for it tonight as well as tomorrow night.