A full moon occurs approximately every 29.5 days when the Moon is on the opposite side of the Earth from the Sun, illuminating the lunar surface as seen from Earth. The countdown above always shows the time remaining until the next full moon.
The countdown above shows the exact date and time of the next full moon (accurate to within ±12 hours).
A full moon occurs approximately every 29.5 days (a synodic month), so there are roughly 12–13 full moons per year.
A supermoon occurs when a full moon coincides with the Moon's closest approach to Earth (perigee), making it appear larger and brighter.
A blue moon is the second full moon in a calendar month, or the third full moon in a season with four full moons. It happens roughly every 2.5 years.