According to modern folklore, a Blue Moon is the second full moon of a calendar month. Learn how this name came to be, in this post.
"August 2012 is a month with two full moons. And, by popular acclaim, that means it’s a Blue Moon month – but it’s Blue in name only. That’s because a Blue Moon is sometimes defined as the second full moon in a calendar month. The first full moon is August 1. The second full moon is August 31, 2012."
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