Once in a Blue Moon!!!

So, people call my blog 'once in a blue moon blog', do they??? Hmm....anyone knows what it really means?? This is what I got when I googled it. er.......erratic googling (:D).

According to the popular definition, it is the second Full Moon to occur in a single calendar month.
The average interval between Full Moons is about 29.5 days, whilst the length of an average month is roughly 30.5 days. This makes it very unlikely that any given month will contain two Full Moons, though it does sometimes happen.
On average, there will be 41 months that have two Full Moons in every century, so you could say that once in a Blue Moon actually means once every two-and-a-half years.

Origin of the phrase:

A blue moon was originally cited as something impossible and later came to mean unlikely. There are rare examples of the moon actually appearing blue, after volcanic eruptions or unusual weather conditions. Another possible derivation is from The Maine Farmers' Almanac. When there were two full moons in a calendar month the first was printed in red, the second in blue.

1528 W. BARLOW Rede Me (1895) 114 Yf they saye the mone is belewe, We must beleve that it is true.

1529 J. FRITH Pistle Christian Reader lxxi. sig. Niv, They wold make men beleue..that ye mone is made of grene chese.

Expect my next post for the next blue moon (:D).....so long!!!