The August Dog Day’s Moon

Last year, there were two full Moons in August, so the second was a “Blue Moon.” That’s not true this year.

There are many names for this month’s Moon and usually I like to choose a different one each year. It could be the Grain Moon, Green Corn Moon, Red Moon (for the reddish hue it often takes on in the summer haze), Mating Moon, Woodcutter’s Moon, Chokeberry Moon, Summertime Moon, Corn Moon, Barley Moon, Dispute Moon, or the Moon When Cherries Turn Black.

I decided to go with the Dog Day’s Moon which refers to the phrase “dog days” a fairly common name for the sultry days of later summer. In the Northern Hemisphere, the dog days of summer are in July and August. In the Southern Hemisphere, they typically occur in January and February, in the midst of the austral summer.

Canis Major constellation map
Canis Major constellation map (Photo credit: Wikipedia)

This name goes back to the ancient Romans who tagged the diēs caniculārēs (dog days) as those hot days that occur along with the star Sirius. Sirius was known as the “Dog Star” because it is the brightest star in the constellation Canis Major (Large Dog). Sirius is also the brightest star in the night sky. The term “Dog Days” was used even earlier by the Greeks.

The Dog Days originally were the days when Sirius rose just before or at the same time as sunrise (heliacal rising), which is no longer true, owing to precession of the equinoxes. In Ancient Rome, the Dog Days ran from July 23/24 through August 23/24.

The Romans sacrificed a red dog in April to appease Sirius, believing that the star was the cause of the sultry weather. Dog Days were popularly believed to be an evil time “the Sea boiled, the Wine turned sour, Dogs grew mad, and all other creatures became languid; causing to man, among other diseases, burning fevers, hysterics, and phrensies.” according to Brady’s Clavis Calendaria (1813).

The ancient Greeks observed that the appearance of Sirius heralded the hot and dry summer, and feared that it caused plants to wilt, men to weaken, and women to become aroused.Due to its brightness, Sirius would have been noted to twinkle more in the unsettled weather conditions of early summer. To Greek observers, this signified certain emanations which caused its malignant influence. Anyone suffering its effects was said to be astroboletos or “star-struck.”

The Old Farmer’s Almanac lists the traditional period of the Dog Days as the 40 days beginning July 3rd and ending August 11th, coinciding with the ancient heliacal (at sunrise) rising of Sirius.


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A lifelong educator on and off the Internet. Random by design and predictably irrational. It's turtles all the way down. Dolce far niente.

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