Heat building as dog days of summer arrive

The “dog days of summer” are upon us, and so is some of the hottest weather of the summer. The latest long-range forecast models show an upper-level ridge of high pressure expanding from the southwestern and central United States eastward into the Midwest, Ohio Valley and Southeast. Temperatures will likely return to the 90s the rest of this week before the ridge breaks down a bit this coming weekend.

Have you ever wondered where the phrase, “dog days of summer” came from? I am sure if you are like me, you always assumed the “dog days” were those days in the middle or late summer where it was so hot outside, that even the dogs would just lie around and pant all day. Or maybe you figured we were already in the dog days. But actually, the original meaning of the term has nothing to do with summer at all. In fact, when the term first came about, it wasn’t even summer.

It turns out the dog days is related to what is called the “dog star” - named Sirius - and its position in the sky. The Greeks and Romans coined the term when the star Sirius appeared to rise before the sun. The Greeks and Romans also believed the dog days brought about a time of war and disaster. Of course in modern time, Sirius appears just before sunrise in late July, which here in the northern hemisphere, is typically when we have the hottest days of the year. Thus the saying – “the dog days of summer”.

But believe it or not, the stars change their position in our sky slowly as the earth wobbles in its rotation, much like a spinning top on a table would do. This is called earth’s axial precession which is a gravity-induced, slow, and continuous change in the orientation of earth’s rotation around its axis. Because of this, the sky “shifts” about one degree every 72 years. It takes about 26,000 years for this rotation to complete itself. So in more simplistic terms, in about 13,000 years, our future ancestors will be terming it the “dog days of winter.” Of course, this also means since astrological signs were determined some 2000 years ago, your actual sign using today’s sky is about a month off! It turns out all this time I thought I was a Pisces, but really I’m an Aries! But that is a story for another time.

Since we live in today’s world, and we have to deal with today’s weather – just be prepared for the dog days of summer to live up to the name this week!

Eric Elwell is WHIO StormCenter 7 Chief Meteorologist. Contact him at eric.elwell@coxinc.com or follow him on Facebook and Twitter.

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