The Reason We Say Dog Days Of Summer

For many people, the arrival of spring is a welcome sight. The days are getting longer, the temperatures finally start to rise out of the single digits, and it becomes enjoyable to spend time outside again. However, in many places, the pleasant warmth of spring is also short-lived. It isn't too long before the really hot weather is in full swing and the dog days of summer arrive, bringing with them muggy air and stifling temperatures.

The dog days are defined as the period of time between early July and early September, when the days tend to be at their hottest in the northern hemisphere, according to Merriam Webster. But why exactly do we call this time of year the "dog days" anyway? It turns out it is not because dogs love them. The phrase actually dates all the way back to the ancient Greeks and Romans, who first coined the term, per National Geographic.

The phrase "dogs days of summer" comes from the positioning of the celestial bodies in the northern hemisphere. In the beginning of the month of July, Sirius, the dog star, begins to rise and set in the same position of the sky as the sun, according to Farmer's Almanac. At this time of year, the sun's location also happens to coincide with the constellation Canis Major, the Greater Dog. Because of the sun's proximity to these canine-themed stars, the ancient Romans began referring to this time of year as "diēs caniculārēs," which translates into "dog days."

The "dog days" are characterized as being the hottest and most stifling days of the year. Ancient civilizations believed that Sirius, which is the brightest star in the sky visible from the earth, was to blame for the oppressive weather. Since it was so bright, ancient Romans believed that the reason that the temperature on earth rose so much during those months was because Sirius was throwing off its own heat. However, we now know that Sirius' position in the sky has nothing to do with hot summer weather, which is caused simply by the position of the earth's tilt.

The "dog days" last for about 40 days in total: the 20 days before Sirius aligns with the sun, and the 20 days afterward, from July 3 to August 11, according to Farmer's Almanac. Ancient Greeks and Romans also believed that the arrival of the dog days could be harbingers of bad luck and misfortune. "If you go back even as far as Homer, The Iliad, it's referring to Sirius as Orion's dog rising, and it describes the star as being associated with war and disaster. All throughout Greek and Roman literature, you found these things," Jay B. Holberg, a senior research scientist at the University of Arizona Lunar & Planetary Laboratory, explained to National Geographic.

However, the original meaning of the phrase has faded over time. These days, many people do think the phrase "dog days" does have to do with actual canines here on earth. Some common explanations for the phrase include the belief that dogs go crazy with the heat or it is simply so hot that even dogs don't want to do anything except lay down in the shade. But while all of this may be true, the true origin of the phrase "dog days of summer" comes from the sun's positioning in the sky.