The night of August 23rd will bring a Black Moon in the heart of astronomical summer: it will be the third of four new moons of the season, a rare occurrence that is not visible to the naked eye but does affect the sky. In the Iberian Peninsula, the exact moment will occur at 08:06 (CEST) —06: 06 (GMT) —, with the lunar disk completely obscured.
This date also coincides with the end of the Perseids , the most popular meteor shower of the summer. The absence of moonlight will provide a darker sky than usual , perfect for those who want to make the most of the "shooting stars" season.
What is a Black Moon and why does it occur?
"Black Moon" is not an official term in astronomy, but rather a popular name for certain unusual new moon occurrences . In this case, we're talking about a seasonal Black Moon : when four new moons occur in the same season, the third one is called a Black Moon.
The reason lies in the length of the synodic month, which is around 29,5 days . This slight discrepancy with our seasons ends up generating, every so often, an additional new moon in the same seasonal period.
The term is also used with other nuances: it can refer to a calendar Black Moon (the second new moon in a single month) or even describe a rare month—usually February— without a new moon or a full moon . In all cases, the moon remains invisible from Earth.
Key dates and times in 2025
This astronomical summer features four consecutive new moons: June 25 , July 24 , August 23 ( the Black Moon , at 08:06 CEST / 06:06 GMT), and September 21. The usual number is three per season, so the August one is an extra.
Although the new moon phase is not visible, those who look west at dusk will be able to try to catch the very thin crescent on August 24 and 25 , shortly after sunset, very low on the horizon.
Can you see it? What you can see that night
A Black Moon is not directly visible: it is, in effect, an invisible new moon . Only during a solar or lunar eclipse can the lunar silhouette be revealed by blocking the sunlight. Even then, its lack of brightness leaves a perfect sky for the dim heavens.
The date coincides with the final stages of the Perseid meteor shower , which is active until August 24. With less light pollution from the moon, the meteor trails are more clearly visible, and the Milky Way appears especially intense in dark locations.
To enjoy it, choose a location away from streetlights and signs, lie down, and let your eyes adjust to the darkness. You don't need a telescope to see the meteors: the naked eye will provide the widest field of view.
Upcoming Black Moons and how often they occur
Black Moons do not follow a single pattern because they depend on the definition used. Roughly speaking, a calendar Black Moon occurs every 29 months, a seasonal Black Moon every 33 months, and a month without a New Moon is very rare (cycles of about 19 years).
- August 23th, 2025: seasonal (third of four new moons in the season).
- August 31th, 2027: calendrical (second new moon of the month).
- August 20th, 2028: seasonal.
- 30 June, 2030: calendrical.
- 20 June, 2031: seasonal.
- January 31, 2033: calendrical.
- February 2033: without new moon.
- March 31th 2033: calendrical.
Curiosities and uses of the term
Sometimes, the expression is also associated with a month without a full moon , something that happened in 2018 and will happen again in 2037. There's no mystery: it's due to the alignment between the lunar cycle and our civil calendar.
Another striking event will occur on August 20, 2028 , when the third new moon of the season coincides with perigee (its closest point to Earth). It won't be visible, like any other new moon, but it's sometimes called a "super black moon."
And in 2033 there will be a peculiar sequence with three linked milestones: two calendar Black Moons (January and March) and a February without a new moon in between.
Quick tips to make the most of your night
With the moon out of the way, it's a great opportunity to observe deep-sky objects and meteors, such as during a blood moon . These guidelines will help enhance your experience, even if you're a beginner.
- Get away from light pollution and look for a wide horizon to the north and east.
- Arrive early to allow your eyes to adjust to the darkness (20-30 minutes).
- Avoid bright screens; if you use one, turn on red mode or turn the brightness down to minimum.
- For meteors, do not use binoculars: covers sky with your gaze and be patient.
- Check the cloud and wind forecast; bring warm clothing and a deck chair.
August's event won't offer a visible moon, but it will offer an exceptionally dark sky that will benefit the Perseids and the rest of the faint sky. With four new moons in the same season—and the third dubbed the Black Moon—summer brings a series of lunar calendar events that, without much fanfare, improve the conditions for stargazing like never before.
