About Full Moon (Blue Moon 2026)
A Blue Moon is the name given to the second full moon in a calendar month, a relatively rare occurrence happening about every 2-3 years. Despite its name, the moon doesn't actually appear blue in color.
The phrase "once in a blue moon" comes from this rarity. May 2026 has two full moons - the Flower Moon on May 1st and this Blue Moon on May 31st.