Dog Days

"Dog Days" are the hottest, most sultry days of summer. In the Northern Hemisphere, the dog days of summer are most commonly experienced in the months of July and August, which typically observe the warmest summer temperatures. In the Southern Hemisphere, they typically occur in January and February, in the midst of the austral summer. The name comes from the ancient belief that Sirius, also called the Dog Star, in close proximity to the sun was responsible for the hot weather.
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from: wikipedia