Blue Moon

The second full moon of May 2026 reaches peak illumination on Sunday, May 31, 2026, at 4:45 a.m. EDT (08:45 UTC). It is a Blue Moon in the modern, monthly sense. To the naked eye, the Moon looks full for about a day on either side of the peak. That makes the evenings of May 30 and May 31 the best nights to watch it rise.

Quick facts

Peak time by US time zone

The Moon is exactly full at one instant worldwide. Only the clock reading changes.

Times are calculated with the open-source astronomy-engine library. Other published sources may differ by about a minute because of rounding.

Is it a supermoon?

No. It is the opposite: at about 406,126 km, the Moon is near apogee (its farthest point, 406,356 km), so this full moon is sometimes called a micromoon. It looks a few percent smaller than average, but the difference is hard to see without a side-by-side photo.

Best viewing tips

Watch the moonrise. In New York City, the Moon rises at about 8:13 p.m. on May 30 (sunset 8:19 p.m.) and at about 9:12 p.m. on May 31 (sunset 8:20 p.m.). Times for your city will differ, so check the Moonlix moonrise page for your location.

Find a clear eastern horizon. Near the horizon, the full moon often looks orange and unusually large. The color comes from Earth's atmosphere filtering out blue light. The size is the well-known Moon illusion, a trick of perception rather than a real change.

Where it sits in the sky. At its highest, this full moon is low in the sky for mid-northern US latitudes. Late-spring full moons ride lower in the southern sky. Late sunsets push moonrise later into the evening, so plan for a later start.

Binoculars and cameras. Ordinary 7x50 or 10x50 binoculars show the dark lunar seas and the bright rays around the crater Tycho. For photos, use a tripod and a telephoto lens, shoot during blue hour just after sunset, and expose for the Moon. A good starting point is ISO 100, f/8 and 1/250 s.

Name origin and folklore

Today, "Blue Moon" usually means the second full moon in a single calendar month. This full moon qualifies because May 2026 also had a full moon on May 1, the Flower Moon. The monthly meaning spread after a 1946 Sky & Telescope article misread an older almanac rule. Under that older seasonal definition, a Blue Moon is the third full moon in an astronomical season that has four. Monthly Blue Moons happen roughly every two to three years. The Moon does not actually look blue; the phrase "once in a blue moon" simply means something rare.

Most full moon names popular in the US today were spread by the Old Farmer's Almanac and the Farmers' Almanac. Native nations had their own names, which varied by region and language, so no single list is "official."

What else is in the sky

The main meteor shower this month is the Eta Aquariids (early May). Check the Moon's phase on the peak night, because bright moonlight hides fainter meteors. Use the May 2026 moon calendar to see every phase, and the daily moon phase pages for illumination on any date.