Blue Moon 2021: How to Watch the Rare Event Tonight

by Suzanne Halliburton
Photo by Nicolas Economou/NurPhoto via Getty Images

Tonight’s your last chance to check out August’s beautiful Blue Moon, the third of the summer season.

Sundown is about 7:45 p.m., so start checking out the sky about an hour later, when the moon starts rising in your time zone. It’ll be next to Jupiter and Saturn.

This moon is certainly unique. After all, why do you think it inspired the phrase “Once in a blue moon.”

The traditional “Blue Moon” is a rare second full moon in the same month. But August has only one full moon, so you probably are wondering why it’s categorized as a blue moon? It’s because this is the third full moon of the summer season. Each season is supposed to have three. But this summer will have four. And in this scenario, the third gets to be the blue moon.

The first two summer full moons were June 24 and July 23. The blue moon already hit its full peak at 8:02 a.m. Eastern time, Sunday. The next full moon of summer is Sept. 20. That’s all according to the Farmers Almanac.

And if you’re wondering, says we see a full moon when the moon is on the opposite side of the Earth from the sun.

Traditionally, each year features a dozen full moons.

August’s full moon also goes by another name. You can call it the Sturgeon Moon. The Maine Farmers Almanac gave it that name, using what the Algonquin tribes called this specific moon. The Algonquin believed that with the help of the Sturgeon Moon, it was easier to catch big fish in the Great Lakes and other large bodies of water.

Other Native American tribes called the August full moon by other names. CNN reported that the Anishnaabe people called it the “berry moon.” The Cherokee described it as the “drying up moon.” The Comanches referred to it, simply, as the “summer moon.” The Creeks dubbed it the “big harvest” moon. Meanwhile, the Hopi people said it was the “moon of joyful.”

Meanwhile, according to NASA, the first reference in English to a Blue Moon was in 1528.

Gordon Johnston wrote in the NASA moon guide: “Speculations on the origin of the term include an old English phrase that means ‘betrayer moon’ or a reference to rare events, such as when dust in the atmosphere makes the moon actually appear blue. Since the 1940’s the term Blue Moon has also been used for the second full moon in a month that has two full moons.” 

The full blue moon occurs about once every 2.7 years. But don’t expect the Blue Moon to be blue here in the United States. That only happens if there’s a lot of smoke in the air, according to Sky & Telescope. However, it’s showing red in Greece.

And if you miss the Blue Moon, it’ll be back in August 2023. So don’t ignore the sky.