A blue moon lasts for the duration of a full moon phase, which is about one night or roughly 29.5 days between full moons. The term "blue moon" refers to the second full moon in a single calendar month or the third full moon in a season with four full moons, not to any color change or special duration of the moon itself. The actual visible full moon generally appears full and bright for about a day, while the full lunar cycle lasts 29.5 days. So, the "blue moon" event is marked by a second full moon occurring in a month and lasts as long as any full moon would—effectively just one night of full brightness within the lunar cycle.
Details on Blue Moon Duration
- The lunar cycle from one full moon to the next is approximately 29.5 days.
- A blue moon happens when the first full moon of the month is early enough to fit a second full moon within the same calendar month.
- The full moon phase itself (peak fullness) lasts roughly a day, although the moon looks nearly full for about three days.
In summary, a blue moon lasts the same length as any full moon, essentially visible fully for one night, occurring as the second full moon in a month occurring about once every two to three years.
