The sixth Full Moon of the year will occur on May 31st at 1:45 am MST. This is a calendar Blue Moon, meaning its the second full moon within a calendar month, a Blue Moon isn’t actually blue in color. This is a micromoon as the location of the moon in its orbit is farthest from Earth, making it appear smaller than normal. The term “Once in a Blue Moon” comes from the fact that Blue Moons are relatively uncommon in occurrence. The next Blue Moon won’t be until December 31st 2028.