The Meaning Behind “The Dog Days of Summer”

August is here! Have you ever wondered why we call August “The Dog Days of Summer?”

The month itself gets its name from Caesar Augustus, adopted son of Julius Caesar. We have always associated the month with heat and humidity and refer to this time of year as the “dog days of summer”.

Why dog days? Why not some other animal? As one might expect there is some history here. The concept dates back to Greek and Roman times. Originally, the days ran from July 24th through August 24th. It was thought that this was an evil time when the sea would boil, wine would turn sour and dogs would go mad. Disease would also be on the rise. The dates for this period have varied somewhat over the centuries with the King James Bible having the span as July 6th and ending September 5th.

As it turns out, the canine connection refers to Sirius (the Dog Star) in the constellation Canis Major (large dog). It is mentioned in Greek poetry as far back as 700 BC. At that time Sirius (the brightest star in the northern hemisphere) was seen to rise just before or at the same time as the sun. The problem here is that a little event, known as precession, has taken place. It seems that the Earth, as it orbits the sun, is not precisely upright but tilts slightly (23.5 degrees from absolute vertical). Neither the sun nor our moon like that and exert gravitational pull to try to correct our tilt. The result is a periodic (about every 26,000 years) wobble, which changes our perspective with respect to how we view the surrounding stars and constellations.

In other words Sirius (the Dog Star) is not there at or before sunrise anymore. Perhaps if the star, viewed by the ancients, had been Deneb in Cygnus, we would have the “Swan days of summer” instead.

In truth, the dog is a good metaphor for heat and humidity. Our friend, the dog, does not come with a huge supply of sweat glands. Those that it does have are frequently covered with a thick coat of fur, which reduces their ability to regulate temperature. The most effective sweat glands old Fido does have are found on the pads of his paws; but even those can do only so much good. The main mechanism for canine temperature control is the very visible panting we observe in our pets.

Please keep this in mind on hot and humid days. If you tie Fido up outside, make sure he, or she, has plenty of water and access to shade. If you take a car ride with your dog and stop to shop, please do not leave your best friend in the car where the temperatures can rise very rapidly.