What Are the Dog Days of Summer?

The “Dog Days” of summer are from July 3 to August 11 each year. They’re usually the hottest and most unbearable days of the season. We often hear about the “Dog Days” of summer, but few know where the expression originated. Some think it’s a reference to the hot, sultry days that are “not fit for a dog.” Others suggest it’s the time of year when the extreme heat drives dogs mad. But where does the term come from? And what does it have to do with dogs? You may be surprised to see is has to do with the stars! Read on.

The “Dog Days” Expression Explained

The constellation Canis Major, the Greater Dog.

The phrase is a reference to Sirius, the Dog Star. During the “Dog Days” period, the Sun occupies the same region of the sky as Sirius, the brightest star visible from any part of Earth. Sirius is a part of the constellation Canis Major, the Greater Dog.

In the summer, Sirius rises and sets with the Sun. On July 23rd, specifically, it is in conjunction with the Sun, and because the star is so bright, the ancient Romans believed it actually gave off heat and added to the Sun’s warmth, accounting for the long stretch of sultry weather. They referred to this time as diēs caniculārēs, or “dog days.”

Thus, the term Dog Days of Summer came to mean the 20 days before and 20 days after this alignment of Sirius with the Sun—July 3 to August 11 each year.

Summer heat is due to the Earth’s tilt

While this period usually is the hottest stretch of summer, the heat is not due to any added radiation from Sirius, regardless of its brightness. The heat of summer is simply a direct result of the Earth’s tilt.

During summer in the Northern Hemisphere, the tilt of the Earth causes the Sun’s rays to hit at a more direct angle, and for a longer period of time throughout the day. This means longer, hotter days.

Autumn Equinox - Vector graphics

What do the “Dog Days” of summer mean to you?

If you plan to take a vacation during this time, read some of our great ideas to stay cool:

Natural Ways To Keep Cool This Summer

Keep 15 Ways To Keep Your Pet Healthy and Hydrated in the Heat

6 Creative Ways To Keep Cool During Hot Summer Days

Can basil Seeds keep you cool?

Farmers' Almanac 2018 - Landfowl

This article was published by the staff at Farmers' Almanac. Do you have a question or an idea for an article? Contact us!

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Vincent Forester

The above chart displaying seasons should say Northern Hemisphere and also display the seasons of the Southern Hemisphere as diametric opposites the seasons of which never occur simultaneously. Thus, global warming is proven to be a fraud.

Ron

My dog has it messed up. She goes out and lays in the sun and the dog days of summer thinking that’s where she should lay. Being a Siberian husky the heat of the sun may never reach her skin because of her coat, maybe that’s why it doesn’t bother her.

Morgan

My mom wouldn’t let me go to the pool during this time. The time of the year it’s the hottest and no pool!

Morgan

No pool time

Gary

When we were children we were told “dog days” were when it was so hot in summer that a dog wouldn’t sleep on a porch but would sleep under it where it was cooler.

Nicole Miles

Animal with less work us is better

Kiss

July 8

Wanda Sutphin

We were told snakes were blind during dog day and would strike at anything.

Wayne

I was a barefoot little boy living on a farm with my grandparents in North Alabama. My grandma told me to never walk barefoot in wet grass during dog days. I, of course, didn’t listen and walked after a rain and morning dew in the grass. I got a few painful sores between my toes before I did as she said. This was in the early 50s.

Mary C

I was raised to know the dog days were a time when sores would not heal fast. Old wives tales were ground into us.

Marie

Me too

Lillian

That is true. Even a insect will fester into a sore and will take longer to heal. So things passed down from older generations were factual

Sara

I have a toe that is constantly draining and will not heal, I wonder if that is why it don’t heal.

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