When does a ''blue moon'' occur?
is this saying based on any reality.as in ''once in a blue moon''
A blue moon is a second full moon that appears in a single solar calendar month, which is a very rare occurrence since one lunar cycle is ~29 days.http://en.wikipedia.org/wiki/Blue_moon
When there's 2 full moons in the same month
It is two full moons in a Month. next one is march 30!! See it for yourself!!!!!!