Florida Georgia Line is set to play the 2nd annual Buckeye Country Superfest in Columbus, OH June. 18th and 19th 2016! Joining them on the bill are country stars Jason.
If a Blue Moon is defined as the second Full Moon in a calendar month, we can easily calculate the mean period for such events because: 1  The synodic period between Full Moons is 29.53 days. 2  There are 12 calendar months in a year of 365.25 days. 3  A mean calendar month is [math]\frac{365.25}{12}\approx30.44[/math] days.
The Moon's phases do not repeat very regularly: the time between two similar syzygies may vary between 29.272 and 29.833 days (see new moon for a detailed account). The reason is that the orbit of the Moon is elliptic, its velocity is not constant, so the time of the true syzygy will differ from the mean syzygy.