The phenomenon behind the phrase 'once in a blue moon' is coming later in May. But there are actually 2 full moons this month.

Is there a full moon tonight? Here's when to look up to see the first of two moons this month and why they are called the flower moon and blue moon.

A rare combination of lunar events, planetary alignments, and deep-sky visibility is set to transform May’s night sky into one of the most rewarding observing windows of the year. From a so-called blue moon to peak meteor activity and an extended view of the Milky Way core,

Oklahomans will get to see not one but two full moons in May, including a rare “once‑in‑a‑blue‑moon” event paired with a micromoon at the end of the month. The full moons will mark the start and the end of the month,

“It’s a second full moon in any month, or a second full moon in a month of any season that has four full moons,” she said. “The first is the definition most commonly used today but stems from some misunderstanding of the definition decades ago.

Shooting stars before dawn, a brilliant meetup between the Moon and Venus and a rare blue moon to end the month.

Every month, WTOP’s Greg Redfern previews the best the sky has to offer stargazers regarding the moon, planets and stars in his “Eyes to the Skies” feature.

One full moon will rise at the beginning of May, while the other will rise at the end of May.