The supermoon on Wednesday will be the third in three months, but it will also be the last of the year.

WGRZ reports, "The full moon is a supermoon because the moon will be at nearly its closest to the Earth. The term was first coined in 1979 by an astrologer named Richard Noelle. He defined a supermoon as a "new or full moon which occurs with the moon coming within 90 percent of its closest approach to Earth." That point where the moon is at its closest is called a perigree."

It's also a special supermoon because it coincides with the Spring equinox. According to WGRZ, "the last time that the two events occurred at the same time was in 1981."