United States – A rare celestial event is set to light up skies across the country this May, as two full moons will appear within a single calendar month — a phenomenon commonly known as a “blue moon.”
According to NASA, the first full moon will occur on May 1, with a second full moon closing out the month on May 31, creating the conditions for what is widely referred to as a calendar blue moon.
A blue moon typically refers to the second full moon in a single month, though historically the term once described a fourth full moon in a season. Today’s more common definition has been widely used since the mid-20th century.
While the name suggests a colorful display, astronomers say the moon will not actually appear blue under normal conditions. A true blue-colored moon is extremely rare and would require specific atmospheric conditions, such as large amounts of dust or smoke particles filtering light in the Earth’s atmosphere — often after major wildfires or volcanic eruptions.
Blue moons occur roughly every two to three years. The last calendar blue moon took place in August 2023, and after this May, the next one is not expected until December 2028.
Skywatchers may also catch additional celestial activity this month, including the Eta Aquariids meteor shower, which peaks in early May. However, visibility could be reduced due to the brightness of the full moon.
