July will see two full moons this year in the lunar progression that leads to a blue moon which only occurs around every three years.
When two full moons happen in the same month, the second is called a blue moon, hence the expression “once in a blue moon.” The last blue moon was August 2012, and the next is expected to come January 2018. It’s safe to say they’re fairly rare.
And while last Wednesday’s moon seemed huge, it’s different than a supermoon, which is what it’s called when the moon is closest to the Earth. That will happen at the end of September, so look for an even larger moon after the July 31 blue moon.