Full Worm Moon March 2023: When Is It and Why Is It Called Lenten?

The March full "Worm" moon is set to grace the night skies—and for Christians, this particular astronomical event has special significance.

The upcoming full moon will be the last of the winter season, coming before the spring equinox—which this year falls on March 20.

In Christianity, this moon is known as the "Lenten Moon," which corresponds with Lent—the traditional period of fasting preceding Easter.

Full moons are lunar phases that occur roughly once every month. At these moments, our natural satellite is located opposite the sun in space, with the Earth positioned directly in between. As a result, every full moon rises around the time of sunset and sets around the time of sunrise.

When the moon turns full, the side facing toward the Earth is completely illuminated by the sun's light, appearing like a perfect circle in the sky.

A full moon in the night sky
Stock image: A full moon in the night. sky. The full moon in March 2023 can be referred to as the "Lenten Moon." iStock

Technically, the moon only turns full at a specific moment in time. The upcoming Worm Moon will reach peak illumination at around 7:40 a.m. Eastern Time, or 4:40 a.m. Pacific Time, on Tuesday, March 7, 2023.

For observers on the East Coast, the moon will be below the horizon at the moment it turns full. But this does not mean that East Coasters will miss out altogether. The moon will actually appear full to most observers for about three days centered on 7:40 a.m. ET/4:40 a.m. PT.

This means you can catch a glimpse of what appears to be a fully illuminated moon after sunset on Monday evening, for example, early Tuesday morning, or even Tuesday evening.

One of the best times to observe the full moon is around moonset or moonrise, when it appears larger and may have an orange hue. This phenomenon is referred to as the "moon illusion"—a perceptual trick of the mind.

"I love admiring the full moon at twilight," astronomer Gianluca Masi from The Virtual Telescope Project (VTP) told Newsweek. "You can enjoy it rising at sunset or setting at dawn, while some light of the sun is around. This makes the local landscape visible, together with the moon, offering a magnificent view. I always try to find the time to enjoy that show."

The VTP is a service provided by the Bellatrix Astronomical Observatory in Ceccano, Italy, that operates and provides access to robotic, remotely operated telescopes.

If you are not able to go outside to catch a glimpse of the full moon, the service will be hosting a livestream so you can enjoy the show from the comfort of your own home.

The livestream, which begins at 1:30 p.m. ET or 10:30 a.m. PT on March 7, will show the full moon rising above the legendary skyline of Rome, Italy, and its famous monuments.

After the previous "mini-moon" that appeared in February—the smallest full moon of the year—the Worm Moon will be perceived as the second smallest of 2023. At the moment the moon turns full in March, it will be located around 249,000 miles away from Earth. This compares to the average distance between the Earth and moon, which is around 239,000 miles.

The traditional names for the full moons in each month of the year come from a variety of places, including Native American, colonial and European sources.

The name "Worm Moon" has long been thought to originate from the fact that earthworms tend to emerge at this time of year in the Northern Hemisphere. This movement provides food for animals such as birds.

But according to The Old Farmer's Almanac, the name may actually refer to beetle larvae, which begin to emerge from the thawing bark of trees and other spots around this time of year.

Other names for the upcoming full moon include the aforementioned Lenten Moon. In Christianity, if the full moon in March had appeared after the spring equinox—making it the first of spring—it would have been referred to as the Paschal Moon rather than the Lenten Moon.

As it stands, the full moon in April, 2023, which falls on the sixth day of the month, will be the first to occur after the spring equinox. The Paschal Moon is used to determine the date of Easter. Namely, Easter Sunday always falls on the first Sunday after the Paschal Full Moon.

There are several other traditional names for the full moon in March, many of which refer to phenomena that characterize the transition between winter and spring.

Different Native American groups have referred to the full moon in March using names such as the Eagle Moon, Goose Moon, Crow Comes Back Moon, Sugar Moon, the Wind Strong Moon, and the Sore Eyes Moon.

Some of these names refer to the appearance of certain animals at this time of year, while the moniker "Wind Strong Moon" hints at the windy weather that often occurs as winter turns into spring.

The final name, meanwhile, is thought to refer to the bright reflection of sunlight off thawing winter snow.