What is a Black Moon?
A Black Moon is a traditional name that is used when there are more new moons than usual in a calendar month or a season. It’s not an official astronomical term.
Monthly Black Moon: Usually there is one new moon in a calendar month. If there are two new moons in a calendar month, then the second new moon of that month is called a monthly Black Moon. It is the most common type of a Black Moon.
Seasonal Black Moon: Usually there are three new moons in a season. If there are four new moons in a season, then the third new moon of that season is called a seasonal Black Moon.
When is the next Black Moon?
The next Black Moon will be on August 23, 2025. It will be a seasonal Black Moon. It will be the third new moon in the season of summer 2025 with four new moons.
Why does a Black Moon occur?
There is always one new moon in a lunar month (lunar cycle of length 29.531 days).
However, it is possible to fit two new moons in a calendar month because the length of a calendar month (30 or 31 days, except for February) is slightly longer than a lunar month. That’s why it is possible to have two new moons in a calendar month.
How rare is a Black Moon?
On average, a calendar month consists of a lunar month and an extra day. So 29 calendar months consist of 29 lunar months and 29 extra days (an extra lunar month). So 29 calendar months consist of 30 lunar months (so 30 new moons).
Since we see an additional new moon every 29 calendar months, a monthly Black Moon occurs on average once every 29 calendar months.
However, a seasonal Black Moon is even rarer, occurring on average once every 33 calendar months.
Why is it called a Black Moon?
A Black Moon is called “black” because it is invisible in the sky. During a Black Moon, the side of the moon that faces our Earth is in complete darkness, like a new moon.
Is it possible to ever see a Black Moon?
A Black Moon is a special kind of a new moon. Now a new moon is visible in the sky during a solar eclipse. So if the date of a Black Moon coincides with the date of a solar eclipse, then it is visible in the sky.
The next Black Moon eclipse will be on May 21, 2031, and be visible from Angola, Congo, Zambia, Tanzania, south India, Malaysia, and Indonesia.
Upcoming Black Moons
Dates of upcoming Black Moons (monthly and seasonal) are given below:
August 31, 2027: Monthly Black Moon
It is the second new moon in the calendar month of August 2027. So it is a monthly Black Moon.
August 20, 2028: Seasonal Black Moon
It is the third new moon in the season of summer 2028 with four new moons. So it is a seasonal Black Moon.
June 30, 2030: Monthly Black Moon
It is the second new moon in the calendar month of June 2030. So it is a monthly Black Moon.
May 21, 2031: Seasonal Black Moon
It is the third new moon in the season of spring 2031 with four new moons. So it is a seasonal Black Moon.
References
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