There will be two full moons during the month of August, as astronomical phenomenon that only happens “once in a blue moon.”
The first full moon is set for Wednesday, August 1. The second will be on August 31. When two full moons occur within a calendar month, the second is called a “blue moon.”
It can also refer to the third full moon in a season with four full moons.
Full moons are separated by 29 days and “blue moons” happen approximately every two and a half years, according to NASA.
The phrase “once in a blue moon,” usually refers to something that is a rare occurrence, and since two full moons in one month doesn’t happen often, people began calling the second a “blue moon.”
Despite it’s name, the moon on August 31 won’t appear blue in color. This only happens if soot and ash particles are in high up in the Earth’s atmosphere. The moon often looks blue after forest fires or volcanic eruptions.