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Once in a Blue Moon
A bit more literal than intended.

When a full moon is not enough to meet a writer's need for the symbolic, they can use the blue moon for it's rarity value. They didn't coin the Stock Phrase "once in a blue moon" from nothing now did they.

Now there's been much confusion over what constitutes a "blue" moon. According to some usages it means the second full moon in a month, or to the third full moon of a season with four full moons.note  The first of those senses is more common, so most of the examples below will refer to that one. Either way, it occurs seven times every 19 years. However, the phrase "once in a blue moon" is much older that either of these usages, and so it appears that the "blue moon" was named for the expression and not vice versa. The earliest attested use the sense that "the moon is blue" is something that is blatantly untrue, so "once in a blue moon" originally meant "never".

You should note that an actual blue moon doesn't constitute the astronomical term, but the effect can be caused by smoke or dust particles in the atmosphere that's usually caused by a forest fire or volcanic ash, as seen in the Real Life section.

"Once in a blue moon" is a phrase that specifically refers to an unlikely or impossible event happening, usually a One In A Million Chance.


  • The Pokémon anime had an episode in which a group of Quagsire traveled to a city to take all sorts of ball-shaped items, which they were supposed to take upstream a river for a celebration for a blue moon. The Quagsire tried to launch the items the closer to the moon they could using water attacks, and next morning all the items returned to the city floating in the river. The citizens considered the last item to appear to be of good luck because it was supposed to be the one which got closest to the moon.

Comic Books

  • A "blue corn moon" is actually mentioned during the song "Colors of the Wind" from the animated Disney movie Pocahontas.
  • The Blue Moon Festival in The Smurfs takes place at every blue moon, which is when Papa Smurf is able to see into the future to foresee what it may hold for his little Smurfs. It also causes a portal within a waterfall to open that transports whoever enters it through time and space. The blue moon becomes an inspiration for Patrick Winslow's latest ad campaign.

  • An Anita Blake novel is called "Blue Moon", referring to both the astrological event and the "Blue Moon cabins".
  • The second novel of The Immortals Series by Alyson Noel is also called "Blue Moon".
  • Simon R Green's Blue Moon Rising, the first of his Forest Kingdom-verse books. When the Blue Moon rises, demons rampage across the land, and this time the Blue Moon isn't setting...
  • In Connie Willis's short story, "Blued Moon", the relationship is reversed. When atmospheric impurities make the moon appear blue, events that would ordinarily be wildly unlikely become ... less so.

Live-Action Television
  • Gilligan's Island episode "Ship Ahoax". When Ginger tells Gilligan's fortune, she says to look for a ship when "the moon is blue". Sure enough, that night the moon is colored blue and a ship passes by the island.
  • On an episode of Charmed the blue moon transformed the sisters into werewolf-like beasts and no explanation of such was ever given.
  • The Pretender episode "Once in a Blue Moon" revolves around a serial killer who strikes on the second full moon of a month and leaves the message "Blue Moon Rising" behind each time.

  • The Rodgers and Hart standard "Blue Moon"
    You saw me standing alone
    Without a dream in my heart
    Without a love of my own
    • There are also songs by (or sung by anyway) Toby Keith, Anna Tsuchily, and Rod Stewart named "Blue Moon."

  • In the prologue of the opera Paul Bunyan, the animals prophesy that Paul Bunyan will be born at the next blue moon. The Old Trees demur: "Don't worry, there won't be a Blue Moon in our lifetime." Then the moon starts turning blue.
  • The Moon Is Blue, at the end of the play:
    Patty: Just think—we only met yesterday.
    Don: It happens—once in a blue moon.

Video Games
  • Persona3: Thanks to using the actual calender for 2009, a blue moon (Moon twice in one month) happens in December. Which coincides with the reveal of The End of the World as We Know It and the second moon is the choice for the Multiple Endings.
  • Dragonvale: The Blue Moon variant released around a real-life blue moon (an extra full moon period within a year).

Western Animation
  • In The Smurfs, baby smurfs are born once in a blue moon.
  • Ruby Gloom, "Once in a Blue Luna": When the moon turns blue the Luna Monster appears. Of course, nobody really believes in the Luna Monster... do they?

Real Life
  • After the Krakatoa eruption in 1883, the moon literally appeared to be blue for over 2 years.
  • Triton, the largest moon of Neptune, is literally colored blue. Guess what color its parent planet actually is!
    • Also, Rhea, the second-largest moon of Saturn, and the only moon in our Solar System to have rings around it (guess which planet does it resemble!), which is apparantly a steel-blue color.

LunacyIndex on the MoonThe Man in the Moon
On a Scale from One to TenStock PhrasesOnce Upon a Time

alternative title(s): Blue Moon
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