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When is the next Blue Moon?

The next Blue Moon is on Wednesday, January 31 2018.

What is a Blue Moon?

The Blue Moon is a second full moon in a Gregorian calendar month. The four phases of the moon, new moon, crescent moon, full moon and waning moon occurring in a period of 29 days approximatetely, so it is possible to have a second full moon in a month. We know that the full moon is not blue, its name originated in medieval England from Old English word belewe, whose meaning is ambiguous, "blue" and "to betray". This event does not occur every year, and when it occurs sometimes occurs more than once in the same year. Even in English, we use the expression "once in a blue moon" to refer to something that happens very rarely.

Blue Moon Images

The following images were taken from the northern and southern hemisphere respectively.

Blue Moon as seen from Cincinnati on 2013-08-31. Image: NASA/Bill Ingalls
Blue Moon as seen from Rio de Janeiro on 2013-08-31. AFP Photo/Vanderlei Almeida

Dates of Blue Moon 2000-2030

According to our lunar calculations, the following table shows the months that have two full moons. The second full moon in the table is called Blue Moon. Note that we have included a link on the occurrence of eclipses. Eclipses are seen in some parts of the world, you can follow the link to learn more about the visibility of the eclipse in your country.

Month and year 1st full moon 2nd full moon Note
December 2001 2001-12-01 (Saturday) 2001-12-30 (Sunday)
August 2004 2004-08-01 (Sunday) 2004-08-30 (Monday)
June 2007 2007-06-01 (Friday) 2007-06-30 (Saturday)
January 2010 2010-01-01 (Friday) 2010-01-30 (Saturday)
March 2010 2010-03-01 (Monday) 2010-03-30 (Tuesday)
August 2012 2012-08-02 (Thursday) 2012-08-31 (Friday) Moons in 2012
July 2015 2015-07-02 (Thursday) 2015-07-31 (Friday) Moons in 2015
January 2018 2018-01-02 (Tuesday) 2018-01-31 (Wednesday) Lunar eclipse on 2018-01-31. Moons in 2018
March 2018 2018-03-02 (Friday) 2018-03-31 (Saturday)
October 2020 2020-10-02 (Friday) 2020-10-31 (Saturday)
August 2023 2023-08-02 (Wednesday) 2023-08-31 (Thursday)
May 2026 2026-05-01 (Friday) 2026-05-31 (Sunday)
January 2029 2029-01-01 (Monday) 2029-01-30 (Tuesday)
March 2029 2029-03-01 (Thursday) 2029-03-30 (Friday)

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Content last updated on 2013-08-01