Here’s why the warmest time of the year is called the “dog days” of summer

PANAMA CITY, Fla. (WJHG/WECP) - During the hot summer months, we’ll hear many people reference the most oppressive days as the “dog days” of summer. There are numerous ideas behind the meaning of the phrase, but the origins of the expression are out of this world.

Some people believe the “dog days” of summer reference those hot summer days when even the dogs are sluggish. According to the Farmer’s Almanac, there are others who think that it references days that are so hot that they’re unfit for dogs. There’s another idea that the days are so steamy the dogs will go mad. However, the actual expression is derived from the stars.

The “dog days” references Sirius, the Dog Star. During the “dog days”, which runs between July 3 and August 11 each year, the Sun is in the same part of the sky as the brightest star, Sirius. Keeping with the dog motif, the “Dog Star” is part of the constellation Canis Major which means the “Greater Dog”. During this time, the Sun and Sirius rises and sets together. According to the Farmer’s Almanac, when the Sun and Sirius would be in conjunction, on July 23, the ancient Romans believed it actually gave off heat and added to the Sun’s warmth because of the brightness of the star. Because of this, the ancient Romans referenced the 20 days before and 20 days after the conjunction of Sirius and the Sun as the “dog days”.

The “dog days” of summer are not extra toasty due to the bright star, instead, it’s due to the Earth’s tilt. During Northern Hemisphere summer, the Northern Hemisphere tilts towards the Sun which causes the Sun’s rays to hit Earth at a more direct angle. That leads to longer days which means hotter days.