As the weather and humidity in central Illinois make it feel more and more like the temperature is over 100°F outside, the IDHH is highlighting the proverbial “dog days” of summer. While the phrase “dog days” or “dog days of summer” might be somewhat familiar, just what are these days and how did this expression enter our cultural lexicon? From an astronomical point of view, the phrase refers to the annual phenomenon in which the bright star Sirius rises into the sky at the same time as the Sun. This heliacal rising allows viewers to see both the Sun and the Sirius star simultaneously, leading to the belief that Sirius intensified or added to the Sun’s heat. In the Northern Hemisphere, this simultaneous rising may be seen during the hottest months of the year, in July and August.
Hellenistic astrologers in the Mediterranean were aware of the star Sirius, calling it the “Dog Star” due to the way it followed the constellation Orion into the night sky. The sweltering and humid weather in the Mediterranean during these months would often cause people to fall ill, and so the connection was made between Sirius’ heliacal rising and its effect on the populations below. A variety of detrimental effects to human activities were attributed with Sirius’ rising such as lethargy, fever, and bad luck, as well as the belief that this hot period brought out madness in dogs, further reinforcing the notion of the “dog days”. While we may no longer blame a summer fever on the “dog days of summer”, there is no denying the potent influence of a heat wave in July to inspire lazy dreams of a nice afternoon spent on the water. Between numerous lakes and ponds, miles of river, and spots like Navy Pier on the shores of Lake Michigan, Illinoisians have plenty of ways to cool down during the hot summer.
Below are a few of our favorite items highlighting ways to enjoy the “dog days of summer” and beat the heat:
Drinks on the Quad – 1936. June 1936. University of St. Francis. Sharing Our Past, A Visual History. Courtesy of the University of St. Francis.
Fire Department Early Water Fights. circa 1915. Huntley Area Public Library. Huntley Area History. Courtesy of the Huntley Area Public Library.
Looking south on Quiver Beach Summer Resort, Havana, Ill. n.d. Published by Tarbill and Ermeling. Eastern Illinois University. Booth Library Postcard Collection. Courtesy of Eastern Illinois University.
Fine Arts Summer Concerts. n.d. Park Ridge Public Library. Pieces of Park Ridge. Courtesy of the Park Ridge Public Library.
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Visit the IDHH to view even more items related to the dog days of summer.