What Are "Dog Days" & Why Do We Refer to Them?

The origin of the expression "dog days" actually has more to do with stars and summer than dogs.

Published January 13, 2024
Golden lab underwater in the pool

If you haven’t used the term “dog days” in conversation, you’ve probably sung the lyrics along with Florence & The Machine. But what exactly are “dog days” anyway? This expression actually has more to do with stars and summer than dogs, although we still like to imagine what true "dog days" entail.

What Are “Dog Days?”

Dog days are the scorching hot days in the peak of summer. That’s why the phrase “the dog days of summer” is often used, but simply saying dog days is just fine because it implies summer. This is usually the period between July and September when temperatures rise.

Origin of "Dog Days" Expression

This expression has roots in ancient Greek astronomy. Sirius, which is the brightest star in the night sky and known as the Dog Star, appears closest to the sun during the hottest days of the summer. People believed its proximity to the sun was responsible for the heat, and the "dog days" of summer was born.

Other Funny Dog Sayings

Have you noticed that a lot of weather-related phrases and other expressions include dogs? We certainly have. Here are a few of our favorites:

“It’s Raining Cats and Dogs.”

It's raining very heavily. 

RELATED: Why Do We Say "It's Raining Cats & Dogs?"

“It’s a Three-Dog-Night”

The night is so cold it would take three dogs to warm up.

“As Sick as a Dog”

Extremely sick.

“Every Dog Has Its Day”

Everyone has success at some point in their lives.

“Dog-Eat-Dog World”

A ruthless environment where people will do anything to succeed.

“Under the Dog’s Paw.”

Controlled by someone or something powerful

“Isn’t Fit for a Dog”

Something of very poor quality.

“Top dog”

Person in charge.

“Let Sleeping Dogs Lie”

Leave things as they are to avoid problems.

Keep Your Dog Cool During the Dog Days of Summer

Now, whenever anyone uses “the dog days of summer,” you’ll know exactly where the expression came from. But while you’re at it, make sure you keep your own furry friend cool during those dog days. Keep them indoors during peak sun hours and provide them with plenty of fresh drinking water. 

What Are "Dog Days" & Why Do We Refer to Them?