The 'Dog Days' of Summer

A dog sitting on a beach with it's ball wearing sunglasses; Spain
Ben Welsh / Getty Images

On days when it's so hot and humid, when even dogs lie around with their tongues out, panting, we say  expression dog days of summer. And while this may be true, it isn't where the expression comes from. Here's the true meaning of the expression plus 4 other little known dog days of summer truths.

1. The expression "dog days" has to do with Sirius, the dog star.

Here's a quick lesson in astronomy: Sirius is the name of the brightest star in the constellation Canis Major (meaning "large dog" in Latin), hence the name "dog star." So the original "dog days" were those days when Sirius would rise just before the sun -- which happened during the summer sky.


2. They occur in July and August.

In ancient times, Sirius would rise with the sun in late July. Today, we observe these dog days from mid-July to mid-August (or mid-February to mid-March in the Southern Hemisphere).  

3. The ancient Greeks and Romans believed the dog days to be a severe time.

In The Iliad, Homer associates the dog days with unsettled spirit:

Sirius rises late in the dark, liquid sky
On summer nights, star of stars,
Orion's Dog they call it, brightest
Of all, but an evil portent, bringing heat
And fevers to suffering humanity.

This, together with their occurrence in summer, is likely the reason why the dog days got their reputation as the hottest, driest, and generally most oppressive days of the year.

4. It isn't always the hottest time of the year.

While the dog days may have a reputation of being the hottest period of summer, this isn't always true. Yes, July and August are considered the hottest months, but the hottest period can vary from year to year.

5. There's no relation to sun dogs.

The term dog days is not to be confused with another canine-named weather phenomena -- sun dogs. Sun dogs are bright, rainbow-colored splotches that appear on either side (or both sides) of the sun. Here, the reference to the word dog is unknown, but most likely comes from the Swedish "dag" which means "mist" or "dew." (The sun + mist forming the rainbow.) 

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Your Citation
Means, Tiffany. "The 'Dog Days' of Summer." ThoughtCo, Jul. 5, 2016, Means, Tiffany. (2016, July 5). The 'Dog Days' of Summer. Retrieved from Means, Tiffany. "The 'Dog Days' of Summer." ThoughtCo. (accessed November 18, 2017).