A rare “blue Moon” will appear in the eastern sky this evening—the second full moon of May 2026. It will rise near the red star Antares in the constellation Scorpius.
The Moon will reach peak illumination on May 31 at 4:45 a.m. ET, or 08:45 GMT, when it appears opposite the Sun in the sky. In the United States, the first appearance of the full Moon above the eastern horizon will be visible on the evening of May 30, around sunset. The exact moonrise time for a specific location can be checked with Time and Date’s tracker.
The reddish light of the supergiant Antares will be visible below and to the left of the Moon. At the same time, Jupiter, Venus and Mercury will line up above the western horizon in the glow of the setting Sun.
Despite the name, the Moon should not be expected to actually turn blue this weekend. Its color may change only near the horizon—at moonrise or moonset, when the light passes through the densest layers of Earth’s atmosphere and takes on orange-red hues.
What Is a “Blue Moon”?
The term “blue Moon” is usually used to describe the second full moon within a single calendar month. The phenomenon occurs roughly once every 2.5 years. The reason is the mismatch between the length of a month in the Gregorian calendar and the 29.5-day lunar cycle, during which the Moon passes through the phases of first quarter, full moon, third quarter and new moon.
Those who want to photograph the Moon should prepare in advance: capturing the lunar disk depends on the right camera settings, a suitable lens and a clear patch of sky.