The phrase the “dog days of summer” is usually said this time of year but many may not know where the phrase comes from.

It’s actually celestial in origin and not named for our furry friends who tend to lay around and be lazy in the heat. 

The ancient Greeks, Romans and even Egyptians all believed that when Sirius, the brightest star in the night sky, was visible during the daytime, it was responsible for additional heat. They thought that when the sun and Sirius were together, it made these summer days the hottest of the year.

Sirius is in the constellation Canis Major and right about now, it’s seen before the sun rises below the constellation Orion. According to Greek mythology, Sirius was one of Orion’s hunting dogs. The ancient Greeks and Romans referred to this time of year as “dies caniculares” or “days of the dog star.”

The ancient Egyptians 5,000 years ago noticed that when Sirius rose with the sun, it was when the annual flooding of the Nile would occur.

By the 1500s, the English world used to call the same hot weeks “dog days.”

Currently, the “dog days” are from July 3 until Aug. 11. The dates have changed over the millennia. They are now several weeks later than they were during ancient times.

Future generations thousands of years from now, will see the dog days even later in the year.