Long ago, it was believed that Sirius, the Dog Star, somehow caused the heat of midsummer.
In Ancient Rome, the "Dog Days" reached from late July to late August. At that time, these dates corresponded to the days on which Sirius rose near the time of sunrise, hence the name of "Dog Days".
Fast forward 2,000 years and the rising of the Dog Star happens earlier in July owing to a shift in the Earth's axis of rotation known as precession. The time of the Dog Days, likewise, has shifted forward and now is accepted to stretch from early July into the first half of August.
By the latter measure, we are now a little beyond the middle of the "Dog Days," so there is plenty of time left for more hot weather.
Story by AccuWeather.com Senior Meteorologist Jim Andrews