![](https://www.cpr.org/cdn-cgi/image/width=3840,quality=75,format=auto/https://wp-cpr.s3.amazonaws.com/uploads/2019/05/danielmcvey-1036.jpg)
… a new or full moon which occurs with the moon at or near (within 90% of) its closest approach to Earth in a given orbit.
That’s a pretty generous definition and allows for many supermoons. By this definition, according to Nolle:
There are 4-6 supermoons a year on average.