You’re not alone if your dog seems especially eager to join you in the swimming pool. In these dog days of summer, people and dogs seem to prefer to take their summer sun in cool pool water.
When the air feels so sultry that the wind doesn’t want to move, swimming sure feels better than running or walking for you and your dog. If you’re out to get exercise, it‘s likely safer, too.
It’s not really about the weather being so hot it’s “not fit for a dog,” as many assume. Nor does it have anything to do with the heat driving dogs (or people) mad, though mad dogs and other ills have been associated with these sticky days since Greek and Roman times.
Our idea of dog days comes to us from the Greeks and Romans, though its origin goes back 5,000 years to Egypt.
They didn’t call it that, but the dog days were such a good sign for the ancient Egyptians that they started their new year when the star Sirius made its first annual appearance on the horizon. It happened every summer just before sunup (the technical term is “heliacal rising of Sirius”). In those days, and at that location, Sirius showed up in the morning sky at the same time as the annual flooding of the Nile.
That annual flood was essential to Egypt’s agriculture. Our long-standing tradition of the dog days starting on July 3, and ending August 11, comes from that Egyptian custom. In truth, for the Philadelphia region we’re just entering dog days on August 11. You can look it up for Philadelphia and many other regions at “Sky and Telescope.”
Our name for Sirius comes from the Greek, but our name Dog Days comes from the Romans. Sirius is the brightest star in Canis Major, the constellation you may recognize as the Large Dog. So it was natural for the Romans to call the sultry weather that came with its return to the summer sky what translates in English to “dog days.”