The popular expression “dog days of summer” has exactly zero to do with the effects of intense summer heat on our canine friends. Both ancient and celestial in origin, the phrase was translated from Latin to English about five hundred years ago and has since morphed in meaning—a common tendency when people don’t know the true origin of a phrase and seek some plausible explanation … perhaps it comes from a day when the weather is so hot that dogs lie around panting and acting lifeless and lazy; or a day not fit for a dog; or a day so hot even mad dogs and Englishmen can’t handle it. The phrase lives on but the original meaning has been long forgotten.
During Roman times (and back to the time of the ancient Greeks as well) there was a period when the dog star Sirius, the brightest star in the constellation Canis Major, rose and set with the sun. This phenomenon occurred for about forty days between early July and mid-August. The Romans thought the combination of the brightest light of the day, the sun, and what was normally the brightest star at night, Sirius, was responsible for the most extreme heat of the summer season. The star sometimes seemed to glow with other colors, and they believed its reddish radiance augmented the heat of the sun.
Geminus, a Greek astronomer from Rhodes, in 70 BCE had a more accurate view: “It is generally believed that Sirius produces the heat of the ‘dog days’ but this is an error, for the star merely marks a season of the year when the sun’s heat is at its greatest.”
Still, the contemporary interpretation of “dog days” has a certain resonance, maybe even appeal, especially in non-pandemic times when one could venture to the ball park on a summer afternoon: hot dogs anyone?!