<P> The term has traditionally referred to an `` extra '' moon , where a year which normally has 12 moons has 13 instead . The `` blue moon '' reference is applied to the third moon in a season with four moons , thus correcting the timing of the last month of a season that would have otherwise been expected too early . This happens every two to three years ( seven times in the Metonic cycle of 19 years ) . The March 1946 issue of Sky & Telescope misinterpreted the traditional definition , which led to the modern colloquial misunderstanding that a blue moon is a second full moon in a single solar calendar month with no seasonal link . </P>
<P> The term has traditionally referred to an `` extra '' moon , where a year which normally has 12 moons has 13 instead . The `` blue moon '' reference is applied to the third moon in a season with four moons , thus correcting the timing of the last month of a season that would have otherwise been expected too early . This happens every two to three years ( seven times in the Metonic cycle of 19 years ) . The March 1946 issue of Sky & Telescope misinterpreted the traditional definition , which led to the modern colloquial misunderstanding that a blue moon is a second full moon in a single solar calendar month with no seasonal link . </P>
where did the blue moon get its name
where did the blue moon get its name
applied to the third moon in a season with four moons , thus correcting the timing of the last month of a season that would have otherwise been expected too early
applied to the third moon in a season with four moons , thus correcting the timing of the last month of a season that would have otherwise been expected too early