Micro Blue Moon: On the night of 31 May 2026, something a little unusual is happening in the sky. The full moon rising that evening goes by a special name: the Micro Blue Moon.
First, what is a Blue Moon?
Most months have one full moon. But occasionally, a month fits two full moons into its calendar, and when that happens, the second one is called a Blue Moon. May 2026 is one of those months. The first full moon arrived on May first, and the second comes around on the 31st of May. That second one is the Blue Moon.
It has nothing to do with the colour of the Moon. The name is simply a way of marking the fact that it is an extra, unusual occurrence. It is also where the phrase “once in a blue moon,” meaning something rare, comes from. This kind of double full moon only happens every two to three years.
So what is a micromoon?
The Moon does not travel around the Earth in a perfect circle. Its orbit is slightly oval-shaped, which means that at certain points in its journey, the Moon is closer to Earth than usual, and at other points it is further away.
When a full moon occurs at the point where the Moon is furthest from Earth, it is called a micromoon. It is essentially the opposite of a supermoon, which is when a full moon occurs at the closest point. Because the Moon is further away during a micromoon, it appears slightly smaller and a little dimmer in the sky, roughly 7 per cent smaller than an average full moon, and up to 14 per cent smaller than a supermoon.
On the 31st of May, the Moon will be at its furthest point from Earth for the entire year, making this not just a micromoon, but the smallest full moon of 2026.
Put it together and you get a Micro Blue Moon
A Micro Blue Moon is simply what you get when both of these things happen at the same time: the Moon is the second full moon of the calendar month (Blue Moon) and it is also at its furthest point from Earth (micromoon). It is a coincidence of calendar timing and orbital geometry, and it does not happen very often.
Micro Blue Moon: Will it look different?
Honestly, not dramatically so. The Moon will not look blue, it never does on a Blue Moon, despite the name. And the difference in size compared to an ordinary full moon is real, but subtle enough that most people would not notice it without a direct comparison. What you will see is a full, bright moon in the southern sky, sitting close to the red star Antares in the constellation Scorpius, which makes for a striking view regardless.
The best time to look is on the evening of the 30th May or the night of the 31st May, when the Moon is low on the horizon just after rising. That low position creates a well-known optical illusion that makes any full moon look larger than it really is, a little ironic, given that this particular moon is technically the smallest of the year.
When is the next one?
The next Blue Moon of any kind will not come until December 2028. So while the Micro Blue Moon on the 31st of May may not look extraordinary to the casual glance, it is a genuinely rare combination of events, and well worth stepping outside to see.
