05/25/2026
The Rare Micro Blue Moon Rises on May 31, 2026 π€
On the last night of May, a full moon will rise that carries two names β and lives up to neither of them. It will not be blue. It will not be enormous. But it will be the rarest and smallest full moon of 2026, and the story behind it stretches back centuries.
What Is a Micro Blue Moon?
A Micro Blue Moon is what happens when two distinct lunar phenomena line up on the same night β a coincidence that does not happen often, and never in quite the same way twice.
The first ingredient is a Blue Moon. Despite the name, the Moon does not actually turn blue. In modern usage, a Blue Moon is the second full moon to occur within a single calendar month. It is an extra full moon, squeezed into a month that would normally have just one. The phrase "once in a blue moon" β meaning something rare β comes directly from how seldom this happens.
The second ingredient is a Micromoon. This occurs when a full moon coincides with the Moon's farthest point from Earth in its elliptical orbit, called apogee. At apogee, the Moon sits roughly 50,000 kilometres farther from us than it does at its closest approach. The result is a full moon that appears slightly smaller and dimmer than average.
Put them together, and you have a Micro Blue Moon β a rare, distant, second-of-the-month full moon. May 31, 2026 will deliver exactly that.