Blue Moon Isn't Often Blue, But Don't Ask Why

Friday, July 31, a rare event, one that occurs once every three years – “once in a blue moon” – will occur. This is when the “blue moon” will take place.

Blue moon occurs once every three years, but "blue" term not exactly accurate

The blue moon marks the point when a full moon appears twice in one month, an event that occurs every three years, and actually has nothing to do with color. The “blue moon” highlights how human calendars are slightly out of balance with lunar calendars and,...