This weekend, skywatchers around the world will witness a rare blue micromoon—a combination of a blue moon and a micromoon. A blue moon occurs when there are two full moons in a single calendar month, an event that happens roughly every two to three years. The second full moon of May 2026 will coincide with the moon reaching apogee, the farthest point in its elliptical orbit from Earth, making it a micromoon. At approximately 252,360 miles (406,134 km) away, this will be the year’s most distant and smallest-appearing full moon.

The term 'blue moon' doesn’t refer to color but to rarity. Despite the name, the moon won’t appear blue. The phenomenon peaks at 4:45 a.m. EDT on May 31, 2026. While the size and brightness difference is subtle—about 6% smaller and 10% dimmer than average—it’s nearly imperceptible to the naked eye. The moon will appear near Antares, a bright red star in the constellation Scorpius, offering a striking visual pairing for observers in the Northern Hemisphere.

Unlike a supermoon, which occurs when the full moon is closest to Earth, a micromoon like this one emphasizes the moon’s elliptical orbit. The event is a reminder of how celestial mechanics shape what we see in the night sky. The next blue micromoon won’t occur until after 2050, making this a rare opportunity for casual stargazers and astronomy enthusiasts alike.