About Blue Moon
A Blue Moon is the second full moon to occur within a single calendar month. Because the lunar cycle is 29.5 days and most months are 30–31 days, a second full moon occasionally fits within one month — roughly every 2.5 years. The phrase 'once in a blue moon' derives from this rarity.
The next Blue Moon is on 31 May 2026 — a Sunday — which is 74 days, approximately 11 weeks or 2.4 months away.
Frequently Asked Questions
How many days until the next Blue Moon?
There are 74 days until the next Blue Moon on 31 May 2026.
When is the next Blue Moon?
The next Blue Moon is on 31 May 2026, a Sunday.
How many weeks until Blue Moon?
There are approximately 11 weeks until Blue Moon.
How many hours until Blue Moon?
There are approximately 1,776 hours until Blue Moon.
What day of the week is Blue Moon?
The next Blue Moon falls on a Sunday, 31 May 2026.
How rare is a Blue Moon?
A Blue Moon occurs roughly every 2.5 years — about 7 times per 19-year Metonic cycle.
Does a Blue Moon actually look blue?
No — the name has nothing to do with colour. It refers to being the second full moon in a calendar month.