What is a blue moon   

Those truly blue moons are even rarer than the other, already rare, blue moon. The next of which will occur on July 31, 2015.

August 2012 is a month with two full moons. And, by popular acclaim, that means it’s a Blue Moon month – but Blue in name only not because of the color.

That’s because a Blue Moon is sometimes defined as the second full moon in a calendar month. The first full moon was August 1. The second full moon is today – August 31, 2012. The second full moon of August 2012 is the Blue Moon.

Happy Blue Moon, everyone!

A blue moon has come to mean two full moons in one calendar month. There is nothing unusual about the moon or its appearance.