A supermoon typically occurs about 3 to 4 times a year. This happens when a full moon coincides with the moon's closest approach to Earth (perigee) during its orbit. Because the moon's orbit is elliptical and its orientation changes, not every full moon is a supermoon, so this event is relatively rare within each year. Some years can have as few as two or as many as five supermoons, but generally, about three to four supermoons are seen annually.
