The moon becomes full only a few hours later at 9:43 PM Eastern Time.
According to NASA, the phenomenon occurs when the moon is "full or almost full and when it is at its closest point to the Earth" or perigee along its slightly elliptical orbit.
When's the next big full moon?
"The Moon orbits Earth in an ellipse, an oval that brings it closer to and farther from Earth as it goes around".
It is also considered to be a significant event that the full moon falls on the same day as the spring equinox and within hours of each other. The "worm" part of the name comes as Native American traditions, marking the time each year when Earth worms began to reemerge from the cold ground as spring drew near. In Canada, it is called the Full Sap Moon as it is during this time that sap of the sugar maple tree starts to flow.
For those hoping to catch a glimpse of the rare moon's glimmer, it's best to head away from the bright lights and smog of major cities to improve your view. A supermoon is slightly brighter and larger than a regular full moon.
This sight is particularly special because it happens to coincide with the March equinox and the beginning of Autumn for the southern hemisphere.
"We don't always have, during the equinox, a full moon, it can be any phase of the moon", said Dr Emily Brunsden, director of the University of York's Astrocampus. Both these days witness equal day and night timings - both the days when the sun is directly above the equator. It marks the first time since March 2000 that a full moon has fallen on the same day as the Spring Equinox, and it's also the last supermoon of the year. The last time they occurred on the same day was on March 20, 1981.
The date of the equinox changes from year to year to account for the fact that the Earth doesn't take exactly 365 days to make a complete revolution around the sun.
Twice a year, around March 20 or 21 and September 22 or 23, the sun's most direct rays shine on the equator.