What is a Black Moon?


Next Black Moon July 31, 2019

The Editors

Much media hype surrounds Moon names, such as "Blood Moon" and "Blue Moon," but have you ever heard of a "Black Moon"? This year, there's a Black Moon on July 31. Here's an explanation of this ominous-sounding name.

What is a Black Moon?

Like "Blood Moon" and "Blue Moon," "Black Moon" is not an astronomical term. In fact, if you ask a sample of astronomers, both professional and amateur, very few will have even heard of it. It's not even a particularly widely known folklore thing. 

As for its definition, some people say it's a "Black Moon" if:

  • There is a new Moon twice in the same month. It's similar to the Blue Moon, which has become a common term for the second full Moon in a month. This is the definition of Black Moon that's used most often.
  • There are NO new Moons in a month. This could only happen in February, and thus is kind of rare, meaning once every 5 to 10 years.
  • The phrase might also simply refer to every new Moon, since we're then seeing the Moon's dark or black side.
  • The phrase is also sometimes applied to mean the third new Moon when there are four in a season, which is actually one of the definitions of a "blue Moon" when the same thing happens to a full Moon.

You can’t see a new Moon. But the gravitational influence of the new Moon and Sun combine to create the stronger tides that we get for a few days around every full Moon and new Moon.

When is the Next Black Moon?

If we go by the standard "two new Moons in one month" definition, Black Moons are slightly rare, occurring about every 32 months (two to three years).

In North America, the next Black Moon will occur on July 31, 2019, at 11:12 P.M. ET (August 1, 2019, at 3:12 UTC). This new Moon is the second of two July 2019 new Moons. (Or, in some time zones, it’s the first of two August 2019 new Moons.

Yes, it's all about scheduling, folks!

What Will You See During a Black Moon?

Uh, not much. Like all new moons, it’ll cross the sky with the Sun during the day.  Humans can't see the new Moon in the Sun's glare.

During the new Moon phase, the Moon is not illuminated by the Sun and seems to disappear from the night sky. A new Moon is practically invisible to the naked eye, so there's nothing to see during a so-called Black Moon.

Remember, there are four quarters of the Moon—the Moon phases. There’s usually a new moon and a full Moon about once a month, because the Moon takes about a month to orbit Earth.

  • You all know the "full Moon," when the entire disk of the Moon is illuminated by the Sun (because they are on opposite sides of the sky).
  • In contrast, the "new Moon" has its dark side facing us. It's not reflecting any of the Sun's light because the Moon is lined up between the Earth and Sun.  

See the monthly Moon phases for your location here.

July 31 New Supermoon

This July, 2019, the new Moon is also a "supermoon" (i.e, the Moon is closest to Earth during its orbit during the new Moon phase.)

With a new supermoon, the tides will be extra large.

Specifically, the high tides are a little higher and low tides are a little lower than average. This is due to gravitational pulls that causes the oceans to bulge a bit more than usual, and called spring tides. (Note: The term "spring tides" has nothing to do with the season of spring. Learn more about spring tides.)

Stars Look Brighter

Although there's not much to see when a Black Moon rises, the good news is that a moonless sky is excellent for stargazing (since the Moon's light won't drown out the stars). Check out our monthly star charts to know what to look for this month.

A day or two after the new Moon, you’ll see the slim crescent Moon in the west after sunset. By August 6, you'll see the Moon in the night sky again.

What do you think about the Black Moon now? Should it carry any significance? Let us know in the comments! Happy stargazing!



Yusuf (not verified)

2 years 3 months ago

This is very special to me as a Muslim. It coincides with the onset of the month of hajj, the pilgrimage to Makka to perform hajj. With the sighting of this moon, the first day of the month of hajj commences. Praise the Lord, Allahu Akbar!

Rononpi (not verified)

2 years 3 months ago

One of the fishing methods frequently used by the old time native Floridians (I don’t think that most of the transplants know about it) is spear fishing for flounder. The technique consists of wading at night in the shallow water of bays, where there is not a lot of wave action, with a lantern and a spear. When you see a flounder dug into the sand on the bottom, you spear it. Flounder are very hard to see because the partially bury themselves in the sand and they change color to mach their surroundings. The only time that they cone close enough to shore where the water is shallow (less than knee deep) enough so that you can spot them is during the new moon. The new moon sets at about the same time as the sun so you have a low tide, which is lower than normal, just as it is getting dark. Two nights before, the night of and two nights after the new moon are the prime times to go flounder gigging.

Chris (not verified)

2 years 3 months ago

I'm fine with Moon names from folklore, like Blue Moon or Black Moon. It's a quick way to refer to a more complex astronomical term. Sure, the media catches on, creating hype, but it does make astronomy more relatable. And supermoons have real effects from tides to people.

Paula (not verified)

2 years 4 months ago

Nothing to see here. Moving on...

Dianne Bohr (not verified)

2 years 4 months ago

The Black Moon this year is on my birthday. What does a Black Moon mean astrologically?