March’s full moon will be the third supermoon in as many months, but don’t take this moon for granted. It’s also the last supermoon of 2019.

This month's supermoon is also special because it coincides with the Spring equinox, on March 20 in the U.S. The full moon occurs at 9:43 p.m. EDT.

Back in March 2000, the moon reached its peak four hours from the Spring equinox, but the last time that the two events occurred at the same time was in 1981.

During an equinox, the sun is directly above the earth's equator, and both hemispheres of the earth get the same amount of daylight and nighttime for one day. There are two equinoxes every year: the vernal equinox in the spring and the autumnal equinox in the fall.

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.

During a supermoon, the full moon might seem a little bigger or brighter than normal. February’s supermoon was the biggest, as it was the closest the moon would ever get to the Earth this year. There was also a supermoon in January. If you missed those two, make sure to catch this month’s because it will be the last one until next year.

March's supermoon is also called the Worm Moon. According to the Farmer's Almanac, the tradition of naming full moons goes back to Native American traditions in North America. Tribes kept track of seasons by giving names to each full moon.