A blue moon is most commonly defined as the second full moon in a calendar month. Contrary to popular belief, it does not have anything to do with the color of the moon.
-- The last blue moon was on May 31, 2007 and the next blue moon is Dec. 31, 2009 -- New Year's Eve!
-- A blue moon occurs every two or three years. Even rarer is a blue moon on New Year's Eve, which only happens approximately every 20 years.
-- A rare event indeed! The last New Year's Eve blue moon was in 1990 and the next one, following 2009, won't be for almost 20 years -- 2028.
-- No blue moon of any kind will occur in the years 2011, 2014, and 2017.
-- Usually months have only one full moon, but occasionally a second one sneaks in. Full moons are separated by 29 days, while most months are 30 or 31 days long. Hence the possibility of fitting two full moons in a single month.
-- Historically, people referred to the twelve full moons by different folk names to prepare for different times of year (harvest moon, growing moon, etc.). In years when there were 13 full moons, the extra, early moon was called the "blue moon."
-- The last blue moon was on May 31, 2007 and the next blue moon is Dec. 31, 2009 -- New Year's Eve!
-- A blue moon occurs every two or three years. Even rarer is a blue moon on New Year's Eve, which only happens approximately every 20 years.
-- A rare event indeed! The last New Year's Eve blue moon was in 1990 and the next one, following 2009, won't be for almost 20 years -- 2028.
-- No blue moon of any kind will occur in the years 2011, 2014, and 2017.
-- Usually months have only one full moon, but occasionally a second one sneaks in. Full moons are separated by 29 days, while most months are 30 or 31 days long. Hence the possibility of fitting two full moons in a single month.
-- Historically, people referred to the twelve full moons by different folk names to prepare for different times of year (harvest moon, growing moon, etc.). In years when there were 13 full moons, the extra, early moon was called the "blue moon."