Why this weekend’s full moon is the smallest and rarest of 2026

Love watching the nightsky and observing celestial events? Then it is time to keep your telescopes ready and keep an eye on the night sky, as this weekend will be the smallest and rarest full moon, which is also a mystical Blue Moon. Unlike the monthly full moons that often go unnoticed, this weekend's full moon is a rare yet unique combination of celestial events: a full moon that is both a "blue moon" and a "micromoon." Despite the name, it won't actually change color. Instead, it will be the smallest full moon of the year shining right next to Antares, a brilliant red star known as the heart of the Scorpion constellation.


Why is it called a Blue Moon?
The term “blue moon” can be confusing because it has absolutely nothing to do with color. According to NASA, a blue moon is simply the second full moon to happen within a single calendar month. Because the lunar cycle lasts about 29.5 days, and our first full moon of May hit right on May 1, a second one manages to squeeze into the calendar on May 31. While they aren't incredibly rare, blue moons don't happen every year.


Once in a Blue Moon
Unlike other moon names passed down through Indigenous traditions and agricultural communities, the blue moon doesn't carry much traditional mythology. Its reputation comes strictly from how infrequently it happens. Over time, the phrase “once in a blue moon” naturally slipped into popular culture to describe events that only happen every once in a while. Even though a blue moon is just the result of our calendar and the lunar cycle getting slightly out of sync, skywatchers still love the occasion.

Unusually Small moon
This month's full moon also carries the title of a "micromoon." This happens when a full moon aligns with the moon reaching "apogee"—the absolute farthest point from Earth in its orbit. Because the moon travels on an elliptical path rather than a perfect circle, its distance from us fluctuates throughout the month.When it is near apogee, the moon looks slightly smaller and dimmer than average. You probably won't spot the difference with the naked eye unless you compare photos, but astronomers estimate a micromoon looks several percent smaller than a typical full moon. The opposite of this is a supermoon, which happens when the full moon is at its closest point to Earth.


A bright Red Star nearby
One of the most striking parts of this weekend's view will be Antares. Located roughly 550 light-years away, Antares is a massive red supergiant star in the constellation Scorpius. To put its size into perspective, if you swapped our Sun out for Antares, its outer edge would swallow everything past the orbit of Mars. Because of its distinct reddish glow, people frequently mistake it for Mars. In fact, the name Antares actually translates to “rival of Mars” for that exact reason. This weekend, Antares will sit right next to the moon, creating a gorgeous contrast between the bright white lunar disk and the deep orange-red star.


When the next Micromoon arrives
If clouds ruin your view this weekend, you won't have to wait very long for a backup choice. The next full micromoon hits on June 29, when the Strawberry Moon also peaks near apogee. This weekend's blue micromoon is actually the middle child of three consecutive micromoons. The trio started back with the Flower Moon on May 1 and will wrap up with June’s full moon. Even though the size difference is subtle, events like this are a perfect reminder that the moon is always changing as it loops around Earth. By pairing two uncommon phenomena into one weekend, it easily earns its spot as one of the most unusual lunar displays of 2026.