Here in the United States, it’s hot. Real hot. Vast areas of the country are experiencing record drought. As the old saying goes, we’re in the midst of the Dog Days of Summer.

You may be surprised to learn that the term “Dog Days of Summer” is based on astronomy. The term dates back to the time of the ancient Egyptians and Romans who associated the first rising of the bright star Sirius — together with the early morning Sun — as marking the onset of very hot weather. In fact, the Romans (falsely) believed the heat from Sirius actually contributed to the hotter weather here on Earth during the summer months. The Egyptians called Sirius “the dog star” (among other names) and also associated its rise with the annual flooding of the Nile river, which was critical to Egyptian agriculture. The Romans, however, saw the Dog Days of Summer as an inauspicious time of year, when disease became rampant in the heat and humidity of summertime Rome.

Sirius is the brightest star in the nighttime sky, and is in the constellation Canis Major, which is Latin for “the large dog.”

The Romans considered the Dog Days of Summer to run from late July through late August. The Greek word ὀπώρα (Opora) appears in the lexicon of the King James Bible, and basically refers to the part of the year between the rising of Sirius and the rising of another star called “Arcturus,” which basically demarcate the period of time we call the Dog Days of Summer.

In folklore, the Dog Days of Summer were perceived as the time of year when dogs went mad with the extreme heat of summer.

Here is a little ditty from folklore about the Dog Days of Summer – a ditty that often appeared in farmers’ almanacs:

Dog days bright and clear
Indicate a happy year;
But when accompanied by rain,
For better times our hopes are vain

The Dog Days even appear in the Charles Dickens’ classic, wintertime tale, A Christmas Carol:

Oh! But he was a tight-fisted hand at the grindstone, Scrooge! a squeezing, wrenching, grasping, scraping, clutching, covetous old sinner! Hard and sharp as flint, from which no steel had ever struck out generous fire; secret, and self-contained, and solitary as an oyster. The cold within him froze his old features, nipped his pointed nose, shrivelled his cheek, stiffened his gait; made his eyes red, his thin lips blue; and spoke out shrewdly in his grating voice. A frosty rime was on his head, and on his eyebrows, and his wiry chin. He carried his own low temperature always about with him; he iced his office in the dog-days; and didn’t thaw it one degree at Christmas.