July 12, 2022 – Dog Days of Summer

We are officially in the Dog Days of Summer. That’s right, the dog days are a specific range of dates! And the reason we call the hottest time of the year “dog days” has nothing to do with our furry four-legged friends! It’s a reference to Sirius, aka the “Dog Star”.
Sirius is the brightest star in the night sky. During the summer months, it rises and sets with the sun. To coincide with Sirius aligning with the sun, the Dog Days of Summer are July 3 to August 11. Ancient astronomers believed that the star contributed to the season’s extreme weather. They thought that the heat of the super bright Sirius combined with the sun made the summer’s scorching temperatures. In reality, of course, it’s the tilt of the Earth’s axis that causes long, hot summer days.
Ancient Romans called this period “days of the dog star” which eventually was translated as just “dog days”. In Egypt, Sirius’ return to the night sky was known as a precursor to the flooding of the Nile River, and they used the star as a sort of watchdog for that annual event.
The dog days of summer that we know are different from ancient civilizations. The Earth’s rotation wobbles, which means Sirius doesn’t appear in the sky at the same time now as it did way back then. And because the rotation will continue to wobble, around 10,000 years from now, Sirius will rise in the middle of winter and it’ll be the “dog days of winter” instead of summer! Learn more here.