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?

Print Friendly, PDF & Email
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!

Notify of

Oldest Most Voted
Inline Feedbacks
View all comments

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.


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!


No pool time


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


July 8

Wanda Sutphin

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


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.


Me too


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


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


The dog is so cute you just want to cuddle him or her .

Susan Higgins

Hi ann: we agree!

Amy Combs

Can you have surgery in dog days and what days

Susan Higgins

Hi Amy, thanks for your note. You should have surgery any time your doctor recommends. But if you’re looking to schedule it during the appropriate phases of the Moon, you can check this chart here:https://www.farmersalmanac.com/calendar/zodiac

Kate T.

Found this article because I was checking dog days dates. I just heard my first mockingbird in several weeks so knew it must be over. Connie Mack, are you in North Florida? I see you just heard them too. Can anyone help point me to the reason why mockingbirds stop singing during dog days? I haven’t been able to find research on it

Kennon Smith

The dog star scares them off.

Connie Mack

The singing stops ! Alerting their young with peeps,and warding off predators with a screech,is all we hear. The singing has started back today! This singing stops for what many call dog days!

Connie Mack

Referring to the Mockingbird!


What exactly does dog days have to do with creek swimming? My parents always told me when I was little I couldn’t swim in the water if it was dog days becUse if I had a sore or anything it would get infected.. Now I tell my kids no swimming in the creek during dog days but why haha … Old wives tale or complete truth?

V. Boggs

I always heard and was told if you had a sore or cut to let a dog lick it and it would heal faster! Never tried it!?


Grew up in the country. I”m 72. We learned the hard way to do what the older people said about ingestion during this period. It IS a fact


I would think the hot weather would make bacteria grow more and the water may not run as much to clean the water as well. Algy grows better in hot weather.



Dan Johnson

Dog day’s in the south was when you had to watch out for snakes because they are shedding their skins and their eyes would have a bluish color to them due to shedding and couldn’t see or sense as well and would strike at you faster than usual .

Larry Parker

I have heard of the term “New Dog Days” any thing to this?


My grandmother always said if it rained the first day of dog days, then it would rain a little everyday for the next 40 days. Conversely, she said that if it didn’t rain the first day of dog days, then it would be dry for the next 40 days. She also said that if dog days set in wet, that if you should have any wounds or open sores during dog days, they would take longer to heal.

V. Boggs

She is right! Rained here the first day and has rained everyday since and is still raining after dog days!


Is there any truth to things that get wet smelling like dog? If so what is the best ways to clean your house without it smelling


Makes sense to me! Thanks, Mike!


Pamala: Every year anglers complain about the “dog days” in mid-to-late summer. The number of boats on the water diminishes as fishing success drops. Anglers are referring to a period of warm water temperatures when seemingly the fish stop biting. Some folks speculate that the fish have sore mouths and have quit feeding. I have heard old timers say, “fish lose their teeth”. There is no scientific or biological evidence of either of those theories. I do know this: Fish are cold-blooded creatures that must eat to survive. The warmer the water, the more they need to eat. The reason anglers aren’t catching has little to do with whether the fish are feeding. They are eating a lot. Fish put on most of their weight during this time.Anglers have good success during those “dog days”. At tournaments, throughout the Midwest, anglers continue to weigh hefty limits of fish. That tells me, most casual anglers simply aren’t applying the right methods to catch fish during the warm water periods. –


Is it true that the mocking birds don’t make noises during “Dog Days”??


Teri Ann
The conjunction of Sirius and the Sun does not occur at the same time in all latitudes, and is not constant in the same region for a long period, hence the variation in calendars regarding the limits of the Dog Days. Some say the period of the dog days lasts 20 days before and after the conjunction of Sirius and the Sun.
In 2015 in the Pacific Time Zone, Sirius rises before the Sun on July 31st, but remains hidden in its glare. When Sirius rises above the Sun at an altitude of 7 degrees it can be seen. This heliacal rising of Sirius occurs August 8, 2015 in San Francisco.


Past wars have proven that wounds do not heal as well. Arizona and New Mexico were two states as well as West Texas were patients with serious respiratory infections were sent in the past.


Do dog days really affect fishing? I heard it said that during dog days the fish doesn’t bite because something tenders their mouth and makes it difficult for them to eat food…. This may be an old wives tale, but I’m curious to hear you take on it.

Teri Ann

I thought ‘dog days’ happened at a slightly different time each year. Sirius is not in alignment with the sun on July 23 every year. I was hoping you could give me exact dates for this year. This information is hard to find. Thanks.

Plan Your Day. Grow Your Life.

Enter your email address to receive our free Newsletter!