Ancient origins of the dog days of summer
By Skip Rigney
I remember being told as a child that the dog days were that long stretch from middle to late summer when the weather hardly changed from day to day. Prolonged heat and humidity had sapped the vigor and verve from most everyone and everything, leaving both people and dogs in our mostly unairconditioned world content to lie around in the shade expending as little energy as possible.
While that is an apt description of most of July, August, and, here near the Gulf Coast, much of September, the expression “dog days” has ancient origins that have nothing to do with lethargic canines panting on the front porch.
Thousands of years ago, before Netflix or ESPN, our ancestors had limited options for night time entertainment. Dark, starry skies stirred their vivid imaginations, conjuring up images of animals, warriors, monsters, and human-looking gods.
People in different cultures connected the same stars differently resulting in different groupings and different figures in the heavens. Apparently, Greek skywatchers thought one group of stars looked like a big dog. In Latin, the constellation went by the name Canis Major, meaning “greater dog.” (There’s also a Canis Minor, or “smaller dog,” but he’s irrelevant to our story.) The Greeks and Romans called the brightest star in the Canis Major group, (in fact, it’s the brightest star in the entire sky), the Dog Star.
The positions of the constellations are constantly changing each night as the earth rotates. Those positions also vary slowly from night to night resulting in big changes from season to season as the earth makes its way around the sun. So, the time that a star rises above and sets below the horizon also varies.
Each year the Dog Star first appears along the horizon of the eastern sky just before sunrise in July or August.
The ancients connected the bright star’s rising and close proximity to the sun with the heat of summer and began to speak of the “dog days” surrounding the star’s appearance. We now understand that, although these starry motions are correlated with the seasons, they don’t cause the weather.
Over the next couple of weeks the Dog Star (also known as Sirius, the name of the Greek god of that star), will rise above the eastern horizon a half hour or so before sunrise each morning. However, unless you’re out on the Gulf, you probably won’t be able to see it. Most of us have too many trees blocking the horizon. By the time the Dog Star has risen high enough in the sky and cleared the tree line, there’s too much sunlight to see the star.
The easiest time for us to see Sirius is actually months from now, long after the dog days have ended. On clear winter nights look for the brightest star in the sky as it rises in the southeast, arcs across the southern sky, and sets in the southwest.
This past week has been plenty hot, but the lack of rain and slightly lower humidity is not what we usually get during dog days.
However, our typical mugginess and scattered mainly afternoon thunderstorms have now returned.
We can expect a stretch of classic south Mississippi dog days.