“Super Moon,” “Harvest Moon,” “Blood Moon,” “Super-Blood Moon” … we have a lot of weird names for the moon’s phases depending on the time of year and today plays host to yet another kind of moon. Ready for it? (drumroll) Introducing the “Worm Moon,” possibly my favorite moon name.
So what is it? Courtesy of The Old Farmer’s Almanac:
March’s Full Moon is traditionally called the Full Worm Moon by the Native Americans who used the Moons to track the seasons; Colonial Americans also used these names, especially those of the local Algonquin tribes who lived between New England and Lake Superior. At the time of this Moon, the ground begins to soften enough for earthworm casts to reappear, inviting the return of robins and migrating birds.
So there you have it, the Worm Moon is the first full moon of March and I was able to get a nice view of it from my backyard late last night. Enjoy!
astroengine.com 
This can’t be accurate. Native America did not have earthworms until they were introduced by Europeans. It is called the worm moon because during this season the worms return to the surface and can even been seen and heard as they work under the previous seasons fallen leaves, but this isn’t a Native American idiom.
Interesting point, I’ll do some more digging. Sounds like the naming likely comes later — or may not be North America specific at all…