Full Worm Moon: Will Conditions In Wisconsin Favor A ‘Moonbow’?

MILWAUKEE, WI — As March's full moon reaches peak illumination over the greater Milwaukee area Monday night into Tuesday morning, it's possible that you'll see worms wriggling out of the ground as well.

Known as the full worm moon, it will be the last full moon of winter. It isn't considered a supermoon, but it will look bigger when it’s near the horizon because of what’s called the “moon illusion,” which makes it look larger when compared with other objects than it does when it’s high in the sky.

The best time to see that effect is around moonrise on Monday. That’s around 6:05 p.m. in Milwaukee. The moon will look spectacularly bright all night, weather permitting. It will rise in the east, possibly setting up some fantastic shots over Lake Michigan for photographers, and set in the west Tuesday morning.

Right now, the National Weather Service forecast a 20 percent chance of rain for Monday night with cloudy conditions, but Tuesday is supposed to be partly sunny.

A bit of rain on either Monday or Tuesday nights when the moon is bright wouldn’t be the worst thing to happen.

You could see a “moonbow,” the nighttime equivalent of a solar rainbow. This rare phenomenon only occurs when the moon is low in the sky, and is refracted through water droplets in the air.

Related: 2023 Guide To Meteor Showers, Supermoons And Full Moons

The colors of a moonbow are every bit as vivid as a rainbow’s, but because they occur when light is low, our eyes can’t detect the full spectrum of color and moonbows often look “spooky-white,” according to The Old Farmer’s Almanac.

However, the publication points out, “If you’re a photographer, the colors of a moonbow will show up in long exposures or on high-speed film.”

The full moon is also a good time to use a macro lens to get super-detailed look as the subterranean world wakes up for the spring. The full worm moon is one of many monikers used to describe Earth’s satellite at this phase in its orbit.

But about those worms: Indigenous tribes named the full moons to keep track of the passing year, choosing the names to reflect the tribe’s customs and culture and local climate and ecology.

Many people believe the full worm moon was so named because it’s the time of year earthworms, awoken by the vibrations of spring raindrops on the soil surface, retreat from their underground burrows, easy prey for the first robins of spring. It’s true enough we’re entering the season for that.

But there’s another explanation.

In the 1760s, Jonathan Carver, the captain of a Massachusetts colonial unit, explorer and writer, visited Native American tribes in North Dakota. In a published account of his expedition, he wrote that the term “worm” referred to beetle larvae that emerge from the thawing bark of trees as spring nears.

The March full moon also has been called the eagle moon, goose moon and the crow moon, but also has been assigned names that correspond with seasons — the sugar moon, because that’s when sap starts to flow in sugar maple trees; the wind strong moon, because winds are typically Strong at this time of year; and the sore eyes moon, which describes blinding rays of sunlight reflected off melting snow.