Black Moon Returns This Weekend

This weekend, the world will experience a rare event known as a black moon. But don't worry, the moon won't actually turn black - it's just a term used to describe either two new moons in the same month or four new moons in a single season.

The summer of 2025 will have four new moons, and the third of them this season receives the black moon designation. "Black moons are rare occurrences," says an astronomer. "A new moon happens about every 29.5 days. Since most months are 30 or 31 days long, and a season is roughly 91 days, a black moon usually requires a new moon to fall on the first day of a month or season."

One thing that makes a black moon more exciting for astronomers than a blue moon (which happens when there are two full moons in a month or four in a single season) is that the new moon phase offers darker skies for viewing stars and planets. In contrast, the bright light of a full moon tends to wash out other objects in the night sky, making them harder to see.

This black moon will also bring a partial solar eclipse, but unfortunately for Americans, this eclipse will only be visible in parts of the Southern Hemisphere. The next full moon will occur on Sept. 7 and will coincide with a lunar eclipse, but this too will only be visible during the daytime for viewers in Asia, Europe, and Africa.