Dog Days

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Also: Dog days of summer.

An idiom with Ancient Roman origins.

Dog on hot summer day

Oh, these long long dog days.

Dog on hot summer day

Oh, these long long dog days.


The dog days of summer are the hottest, longest, most humid days of summer, between early July and early September in the Northern hemisphere and January and February in the Southern hemisphere. The idiom also can refer to a period stagnation or inactivity, alluding to how people do not want to do much during those hot sultry months, except to lie around and try to stay cool.


The idiom was used in the title of the movie Dog Day Afternoon, starring Al Pacino.

"We'll never get through these dog days if we don't get a new air conditioner."

"It was the dog days of summer, and all the kids were out playing games in the park."

"It's tough to stay in business during these dog days when all the tourists have left."


The term dog days comes from the ancient Roman dies caniculares, which was associated with Sirius, the Dog Star. Sirius was named thus for being the brightest star in the constellation Canis Major or 'Large Dog.'

The Dog Star rose and set with the sun during the hottest weeks of the year, from July to August. It was believed that the heat from the Dog Star actually combined with the heat from the sun to cause this period to be extra-hot, leading to these months being called the dog days. It has long been suggested that the name also came from the effect the heat had on dogs. The Romans would sacrifice a dog at the beginning of the Dog Days, in hopes that the star would not send so much heat, as a particularly dry hot summer could cause all sorts of hardships, including plague.

This associating with dogs with sacrifice, death, and the hot days of summer in Rome and in other cultures of the Northern Hemisphere had a lot to do with the change from a hunting to an agricultural lifestyle. The ancient Greeks had seen Sirius, and Procyon the Lesser Dog-star, as following their master Orion, the great hunter in the night sky. When a dependence on agriculture became more the norm, dog sacrifices, among other purposes, were meant to ensure a good agricultural season. However, there may have been a practical reason for the killing of dogs during the "dog days." During the hottest months, as in Ancient Greece, the dog days were a time of increased incidence of rabies, and controlling the canine population could help ensure the public health.

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