What is a Black Moon?

There are several definitions of Black Moon. It can be the third New Moon in an astronomical season with four New Moons or the second New Moon in the same calendar month.

Illustration image
A Black Moon can be a New Moon.
©bigstockphoto.com/mr. Smith

Black Moon is not a well known term in the astronomy world. In recent years, the term has been made popular by astrologers and followers of the Wiccan religion.

No Single Definition

There is no single accepted definition of a Black Moon. The term has been commonly used to refer to any of the following phenomena associated with the New Moon:

  • Second New Moon in a calendar month: These Black Moons occur relatively often – once every 2.5 years.
  • Third new moon in a season of four New Moons: Astronomers divide a year into fourseasons – spring, summer, fall (autumn), and winter. Usually, each season has 3 months and 3 New Moons. When a season has 4 New Moons, the 3rd New Moon is called a Black Moon.
  • A calendar month without a New Moon: This can only happen in the month of February. When this occurs, January and March will have two New Moons, instead of the usual one New Moon.
  • A calendar month without a Full Moon: About once every 19 years, the month of February does not have a Full Moon. Instead, January and March have two Full Moons each. The next Black Moon by this definition will occur in February 2018.

Upcoming Black Moon

October 2016 will have two New Moons – on October 1, 2016 and on October 30, 2016. The second New Moon on October 30, 2016 will be a Black Moon.

Year Date/Month Type
2016 Sep 30 Second New Moon in a single calendar month
2017 Aug 21 Third New Moon in a season with four New Moons
2018 Feb Calendar month without a Full Moon

Ritual Significance

Black Moons hold special significance to people who practise certain forms of Pagan religions and who believe certain actions become more potent when performed on the night of a Black Moon.

Blue Moon

Blue Moon is a term used to descibe various combinations of Full Moons. It can either be the second Full Moon in the same calendar month or the third Full Moon in an astronomical season of four Full Moons.

From: http://www.timeanddate.com/astronomy/moon/black-moon.html