The Dog Days of summer begin today in CNY but why? What is it?  The answer is not what you think.

The Dog Days are not when you have to watch out for heat stroke with Fido or when your pooches panting hard because of the humid heat. It used to coincide with the rising of the Dog Star Sirius.

Sirius, also known as the Dog Star or Sirius A, is the brightest star in Earth's night sky. The name means "glowing" in Greek. With a visual magnitude of -1.46, the star is outshone only by several planets as well as the International Space Station. Because Sirius is so bright, it was well-known to the ancients. What came as a surprise to astronomers was the discovery of a companion star, Sirius B, in 1862. [space.com]

In ancient times Egyptians, the ancient Greeks, and Romans thought the heat, humidity, drought, sickness and ultimately death was due to the arrival of Sirius combined with the Sun. They also believed Sirius brought the Nile River’s flood season.

According to The Old Farmer’s Almanac, the Dog Days of summer are traditionally the 40 days beginning July 3 and ending August 11, which coincide with the dawn rising of the Sirius, the Dog Star.

The Old Farmer’s Almanac for Kids tells us under the right conditions the Sirius Star can be seen with the naked eye during the day. Sirius is one star in a group of stars that form the constellation Canis Major, meaning “Greater Dog" hence the nickname Dog Star.

Old-timers believed that rainfall on the dog days was a bad omen, as foretold in this verse:
Dog Days bright and clear
Indicate a happy year;
But when accompanied by rain,
For better times, our hopes are vain.

Dog Days are approaching; you must, therefore, make both hay and haste while the Sun shines, for when old Sirius takes command of the weather, he is such an unsteady, crazy dog, there is no dependence upon him. [The Old Farmer’s Almanac, 1817]