Overview
- Skywatchers will get a monthly Blue Moon on May 31, 2026, defined as the second full moon in the same calendar month.
- Despite the name, the Moon will not look blue, which happens only in rare smoke or volcanic ash conditions that filter out red light.
- The full Moon will be easy to see where skies are clear, with the best views near moonrise from dark locations away from city lights.
- In India, the Moon will appear full after sunset on May 31 even though the peak occurs earlier in the afternoon local time.
- The term has two roots—Maine Farmer’s Almanac in 1937 and a 1946 Sky & Telescope misreading—and such events recur every two to three years, with an unusual Blue Moon on December 31, 2028 expected to align with a supermoon and a total lunar eclipse.