Blue Moon Tonight! But Why Is It So Rare?

So, there is a Blue Moon tonight in the night sky.  And do you know how often that happens?  Once in a blue moon!  C'mon... I had to!  Seriously, this isn't your typical blue moon.

The definition of a "blue moon," is when there is a second full moon in a month.  That usually happens about twice a year.  But tonight's blue moon is not that kind.

Tonight's blue moon is the fourth full moon of the summer season, known as a "seasonal blue moon."  Typically, there are only three full moons in any one season.  This type of blue moon hasn't happened in about three years and won't happen again until 2016.

Weather.com says that it will be at it's brightest and most visible about 8:45pm CST.  A seasonal blue moon is said to be particularly brilliant sight because it is exactly opposite the sun and super illuminated.

And no, it won't actually be blue.

Link:  Learn more about tonight's seasonal blue moon.