What and When Are the Dog Days of Summer?
The Dog Days of Summer are upon us! So, what does this quirky phrase mean? It’s more than just a hot spell. The ancient origins of “Dog Days” might surprise you. Learn more.
What Are the Dog Days of Summer?
The term “Dog Days” traditionally refers to a period of particularly hot and humid weather occurring during the summer months of July and August in the Northern Hemisphere.
Dog Days bright and clear
Indicate a happy year;
But when accompanied by rain,
For better times, our hopes are vain.
In ancient Greece and Rome, the Dog Days were believed to be a time of drought, bad luck, and unrest, when dogs and men alike would be driven mad by the extreme heat! Today, the phrase doesn’t conjure up such bad imagery. Instead, the Dog Days are associated purely with the time of summer’s peak temperatures and humidity.
Why Are They Called the “Dog Days” of Summer?
This period of sweltering weather coincides with the year’s heliacal (meaning “at sunrise”) rising of Sirius, the Dog Star. Sirius is part of the constellation Canis Majoris—the “Greater Dog”—which is where Sirius gets its canine nickname, as well as its official name, Alpha Canis Majoris. Sirius is the brightest star in the sky, not including our own Sun.
In ancient Greece, Egypt, and Rome, it was believed that Sirius’s dawn rising in mid-to-late summer contributed to the extreme weather of the season. In other words, the “combined heat” of super-bright Sirius and our Sun was thought to be the cause of summer’s sweltering temperatures. The name “Sirius” even stems from the Ancient Greek seírios, meaning “scorching.”
For the ancient Egyptians, Sirius’s dawn rising (known to them as Sothis) also coincided with the Nile River’s flood season. They used the star as a “watchdog” for that event.
Of course, the appearance of Sirius does not actually affect seasonal weather here on Earth, but its appearance during the hottest part of summer ensures that the lore surrounding the star lives on today!
When Are the Dog Days of Summer?
The exact dates of the Dog Days can vary from source to source, and because they are traditionally tied to the dawn rising of Sirius, they have changed over time. However, most sources agree that the Dog Days occur in mid-to-late summer.
Here at the Old Farmer’s Almanac, we consider the Dog Days to be the 40 days beginning July 3 and ending August 11. These days occur soon after the summer solstice in late June, which also tends to be the beginning of the worst of summer’s heat.
The Brightest Star in the Sky
Sirius is the brightest star in the sky if you don’t count our own Sun. Under the right conditions, it can even be seen with the naked eye during the day. Sirius is one star in a group of stars that form the constellation Canis Major, meaning “Greater Dog.” It’s no surprise, then, that the nickname of this big, bold star became “the Dog Star.”
https://www.almanac.com/content/what-are-dog-days-summer