The Blue Moon in Sagittarius - Once in a Blue Moon, the Archer aims straight at the truth. The Astrology A Blazing Beacon of Truth Welcome to one of the rarest lunations of 2026! This Blue Moon arrives at 9°56' Sagittarius on May 31st, 2026 — the second full moon of May and a genuinely rare lunation. A calendrical Blue Moon occurs when two full moons fall within a single calendar month; the last was the Scorpio full moon on May 1st. This makes the entire month of May an extra