Rare Blue Moon on 31 May Visible from Indonesia, Note the Timing
The Blue Moon phenomenon will occur on 31 May 2026, drawing public interest as a notable astronomical event. The spectacle is expected to be visible across various regions of Indonesia when the weather is clear.
The term “Blue Moon” often sparks curiosity due to its unusual name, leading many to believe the moon will actually turn blue. However, in astronomical terms, it refers to an extra full moon within a specific period, not a change in colour.
According to NASA, there are two types of Blue Moons. The first is the seasonal Blue Moon, which is the third full moon in a season with four full moons. The second is the monthly Blue Moon, occurring when two full moons happen within the same calendar month.
The 31 May 2026 event is a monthly Blue Moon, as it will feature two full moons in the same month. Such occurrences are rare, making it a noteworthy event for skywatchers.
As reported by Time and Date, the peak of the Blue Moon phase is expected on 31 May 2026. In Indonesia, the full moon will become visible after sunset between approximately 17:30 and 18:00 local time and remain clearly visible throughout the night.
The best time to observe the Blue Moon is from early evening until midnight when the moon is high in the sky. Viewing can be done without special equipment provided the sky is clear and unobstructed by clouds.
To enhance visibility, the public is advised to find locations with open skies and minimal light pollution. Hilltops, beaches, and remote areas away from urban centres are ideal spots for enjoying the full moon phenomenon.
Contrary to popular belief, a Blue Moon does not cause the moon to appear blue. NASA explains that the term is purely an astronomical label for an additional full moon. Although the moon can sometimes appear bluish due to atmospheric particles like smoke or dust, this is unrelated to the Blue Moon phenomenon and extremely rare.
The Blue Moon is one of the infrequent astronomical events in a calendar year, making it a special occasion for the public and sky enthusiasts to observe the full moon in the night sky.