A Rare Blue Moon in August 2024
By Anne Buckle. Published 12-Aug-2024
This month a special Full Moon will light up our sky. It’s the Sturgeon Moon, but also a Blue Moon. How does that happen?
The Full Moon on August 19 is both the Sturgeon Moon and a Blue Moon.
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The Sturgeon Blue Moon
On August 19 at 18:25 UTC, the Sturgeon Blue Moon will light up our night skies. It may look like a normal Full Moon, but it is slightly rarer than the one you see almost every month. This is because it’s a Blue Moon and also the Sturgeon Moon, the Full Moon in August.
The Sturgeon Blue Moon in your time zone
So, What Is a Blue Moon?
There are two different definitions for a Blue Moon, and both have to do with fitting the Full Moon into our modern calendar:
- A seasonal Blue Moon is the third Full Moon of an astronomical season with four Full Moons.
- A monthly Blue Moon is the second Full Moon in a calendar month with two Full Moons.
The Blue Moon on August 19 is a seasonal Blue Moon. After this, you have to wait until May 31, 2026 for a monthly Blue Moon.
Why Two Definitions of a Blue Moon?
You might be wondering why there are two definitions for a Blue Moon. It all boils down to a misunderstanding that took hold in the public in the not-so-distant past.
The original and oldest definition is the seasonal Blue Moon and can be traced back to the old Maine Farmer’s Almanac. According to the almanac, this extra Full Moon upset the Christian calendar. So in an effort to avoid shifting other significant Full Moons in the church’s calendar—like the Lenten Moon and the Pachal Moon—it decided to name the extra Full Moon a Blue Moon.
The other definition of a Blue Moon, the second Full Moon in a month, is based on a misinterpretation printed in a 1946 edition of Sky & Telescope magazine.
Moonrise happens around sunset when there is a Full Moon. It can make for beautiful colors in the sky.
©iStockphoto.com/ihsanokur
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And Why Is It Happening Now?
Now that we have the definitions out of the way: why are there four Full Moons in this astronomical season?
It has to do with the early timing of the first Full Moon. This season started at the solstice on June 20, and only two days later, the Sun, Earth, and the Moon lined up for a Full Strawberry Moon.
Because the Full Moon was so early in the season, it gave the Moon time to run through its lunar cycle from New Moon to Full Moon about three and a half times, just managing to squeeze in another Full Moon before the astronomical season ends at the equinox on September 22, 2024.
How Rare Are Blue Moons?
Chances are that you’ve heard the phrase “once in a Blue Moon.” It is often used to describe something that happens rarely, so how frequently do Blue Moons happen? Well, because we use two definitions, they happen roughly every two or three years.
Seasonal Blue Moons take place slightly less frequently than monthly Blue Moons. When we add up the Blue Moons in the 1100 years between 1550 and 2650, there are 408 seasonal and 456 monthly Blue Moons.