‘Full Flower Moon’ in May Will Be a Micro Moon—What It Means and What to Expect

An illustration of the Full Flower Moon that occurs in May. (Matt Cardy/Getty Images) Shutterstock/Oleksandr Lytvynenko /Peredniankina/Hal_P/grey_and

As full moons go, next month’s will be beyond the ordinary. The so-called Full Pink Moon in May, named after the month’s blooms, will appear to have shrunk to a miniature size and dimmed noticeably darker, and will also block out the red star Antares—the “heart of the scorpion” in Scorpius.

Peaking on May 12 at 12:56 p.m. EDT, the Full Pink Moon will rise to the east and hang relatively low in the sky, as it will around the spring equinox. But a keen observer might notice a distinct difference in its appearance.

It’s no trick of the eye, nor is it the “moon illusion.” This May full moon will be a micro moon, which is the opposite of a super moon—where the moon appears larger than normal, as much as 8 percent larger, and glows up to 15 percent brighter. A micro moon appears about 5 percent smaller and 10 percent dimmer than usual.

But the moon didn’t actually shrink. Nor is it a mere illusion; the moon will occupy less area in the sky.

The scientific explanation, according to Time and Date, tells us that because the moon’s orbital path isn’t precisely circular, but rather is elliptical, sometimes the moon is closer to Earth and at other times farther away. When it nears its closest point to us, its perigee, it becomes a super moon; it becomes a micro moon at its farthest point, its apogee.

Yet this difference in size and brightness could easily escape the casual observer’s notice, though it will be apparent to the human eye if you look for it.

The Full Pink Moon’s position among the stars is relatively constant year on year, trading positions between the constellations Libra and Scorpio. This year it will fall in Libra where one may spy the constellation’s brightest star, Zubenelgenubi, a magnitude-2 star, nearby. Moon gazers will need to find a clear view of the horizon to see this.

The Full Flower Moon sets over Stonehenge in Amesbury, United Kingdom, on May 26, 2021. Webster/Getty Images

On the night after, the moon will have crossed over into Scorpio where it will form a conjunction with the reddish magnitude 1.1 star Antares—known as the “heart of the scorpion” because it’s centred within Scorpio. At this point, the moon will still appear full though it technically won’t be (the moment of technical fullness is but a split second).

As an added bonus—only for observers way down in the horn of South America unfortunately—an extra rare astronomical phenomenon is in store. Viewing from certain locales, on May 13 and 14, from 10:31 p.m. until 2:57 a.m., the moon will completely cover over—or occult—the red star Antares, hiding it from view.

Astronomers expect this occultation to be spectacular.

Why Is It Called The ‘Flower Moon’?

For many years, people have called May’s full moon the Flower Moon—as far back as colonial times. Every moon in the lunar calendar has similarly colorful monikers, most alluding to the seasons in which they fall. There’s the Beaver Moon in autumn and Cold Moon in winter; each denotes the entire lunar month, not just the full moon.

Both native Americans and settlers derived many of the moon names still in use today, according to The Old Farmer’s Almanac, deriving them by observing local climates and seasonal peculiarities. Most notably, they observed spring growth. Flower Moon is said to originate from the Algonquin tribespeople, for instance, while the Budding Moon and Leaf Budding Moon were named by the Cree.

Naturally, wildlife and livestock were also a big part of life and became associated with begetting animal moons names in spring. There’s the Moon of the Shedding Ponies used by the Oglala peoples and the Egg Laying Moon and Frog Moon of the Cree.

The nicknames are as proliferous as spring itself.

American explorer Jonathan Carver, who stayed with the Dakota peoples while exploring the Great Lakes region, wrote about the lore surrounding Native calendars. In his 1798 publication “Travels Through the Interior Parts of North America: 1766, 1767, 1768,” he noted the Dakota name for May’s full moon: “Month of Flowers.”