The expression “Dog Days” refers to the hottest stretch of summer, now considered from about July 3 to August 11 in the Northern Hemisphere — a time symbolizing heat, lethargy, and restless weather.
The origin lies not in real dogs panting under the sun, but in the stars. The ancient Greeks and Romans noticed that the Dog Star, Sirius, rose and set with the sun during this period. Sirius, the brightest star in the constellation Canis Major (“Greater Dog”), was believed to intensify the sun’s heat, bringing drought, fever, and exhaustion. The Romans called this period dies caniculares, literally “days of the dog.” Over time, “dog days” came to describe any spell of sweltering weather or sluggish activity.
The phrase first appeared in English as early as 1538, when schoolmaster John Withals noted in his A Shorte Dictionarie for Yonge Begynners, “Caniculares dies, the Dogge dayes beginne nowe,” marking the onset of an oppressive season. Withals was an English lexicographer and schoolmaster who compiled one of the earliest bilingual (Latin–English) dictionaries intended for students. Later, writers like Charles Dickens and Mark Twain used it metaphorically to evoke stillness and stagnation: “It was the dog-days, and the streets were empty,” wrote Dickens in The Mystery of Edwin Drood.
Today, we still say things like “the dog days of summer drag on” or even “the dog days of a project,” echoing that ancient belief that when Sirius burns bright, everything slows down.
