![Blue moon](https://www.xwhos.com/photo/whois_blue_moon_profile_834727.webp)
Blue moon
A blue moon is an additional full moon that appears in a subdivision of a year: either the third of four full moons in a season, or a second full moon in a month of the common calendar.
A blue moon is an additional full moon that appears in a subdivision of a year: either the third of four full moons in a season, or a second full moon in a month of the common calendar.