Where did the saying 'once in a blue moon' originate and what does it mean?

Answer 1

I was always told that it referred to the second full moon in a month but here is a website that delves into that reason along with "It states that it was used as in to say that something would never happen" and "that there are even historical examples of the moon actually turning blue". It's pretty interesting. Take a minute to visit this website.

Answer 2

July 7, 2004: When you hear someone say "Once in a Blue Moon…" you know what they mean: Rare. Seldom. Maybe even absurd. After all, when was the last time you saw the moon turn blue?


SPACE.com) -- Some almanacs and calendars assert when two full moons occur within a calendar month, that the second full moon is called the "Blue Moon."

The phrase "Once in a blue moon" was first noted in 1824 and refers to occurrences that are uncommon, perhaps even rare

It was not until the year 1999 that the origin of the calendrical term "Blue Moon" was at long last discovered



Here are some of the ways the expression "Blue Moon' has been used in the past. But, surprisingly, the meaning most used today has come into general use only during the last few years. Most of what follows is paraphrased from 'Once in a Blue Moon' by Philip Hiscock, Sky and Telescope, March 1999, page 53. I guess he coined the phrase.

Seven uses of 'Blue Moon':
1. As an ABSURDITY. 'He would argue that the moon is blue!', as if to say, he would argue that black is white! Such expressions can be found in the literature of the 16th century.

2. NEVER. "I wouldn't be seen with him even if the moon
turned blue." This use was apparently common in the 1900's.

3. ACTUALLY IS BLUE. Seen against a blue sky in daytime or twilight, our eyes may see the moon as a bluish tint. Smoke or dust in the air can emphasize the blue or other color.

4. RARE. An actual blue moon color is fairly uncommon, so the term took on the meaning of rarity or, 'I only do this once in a blue moon'.

5. SADNESS, LONELINESS. Well, there is only one up there! It can and does console us when we are alone and blue.
Remember all the old song, 'Blue Moon, I saw you standing alone...'.

6. There is a drink, made from Blue Curaçao, called BLUE MOON

7. SECOND FULL MOON IN A CALENDAR MONTH. Because 11 of the twelve months have more days than the lunar cycle of 29 1/2 days, it is easily possible for a month to have two full moons. These happen irregularly because of the different number of days in months, but there are 7 'blue moon' months in the 19-year Metonic cycle (repetition of moon phases on nearly the same calendar dates).

The author, Philip Hiscock, traced the earliest published reference to the 'second full moon in a month' to the 1937 Maine Farmers' Almanac, (Charles E. Nash & Son, Augusta).


Thank you for this interesting question, which i wondered sometime. I researched thru a lot of reading materials on this phrase. and this is a brief compilation. Hope it helps!

Answer 3

When a single month has two full moons, the second full moon is called a Blue Moon.

Another definition of the blue moon is the third full moon that occurs in a season of the year which has four full moons (usually each season has only three full moons.)

Answer 4

A 'blue moon' is the second full moon in the same month, which does not happen very often, hence the saying 'once every blue moon'.

Answer 5

Saying the moon was blue was equivalent to saying the moon was made of green cheese; it indicated an obvious absurdity. In the 19th century, the phrase "until a blue moon", meaning "never". The phrase, "once in a blue moon" today have come to mean "every now and then" or rarely"- whether it gained that meaning through association with the lunar event remains uncertain.

Answer 6

If thereare two full moons in a month, the second one is called a blue moon,

Farmer's moon if it happens in spring or summer and Hunter's moon if it happens in fall or winter, in which their are two full moons in a month, the second one is called a blue moon. Because their are two full moons their is more light for farmers to farm and hunters to hunt at night if they do so.

Answer 7

I am unsure as to when it originated. I do know that it means "rarely"--basically, a blue moon is when there are two full moons in the same month (I think), which is pretty rare. Check out Wikipedia...there is probably something more concrete there: www.wikipedia.org

Answer 8

originate i can not answer that one but it means every now and then.