A rare lunar phase called a Black Moon is expected to be in the night sky later this week. Here's when it will happen.

Summer 2025 in the Northern Hemisphere started with a new moon on June 25, followed by July 23, Aug. 3 and Sept. 21. With four new moons squeezed into the season, the Aug. 23 new moon becomes the Black Moon. Seasonal Black Moons, like the one on Aug. 23, happen only about once every 33 months.