The time between mid July and mid August is known as the dog days of summer.
This is when the weather doesn't change much and it's the hottest and driest part of the year. Mid-summer is called the dog days because the brightest star in Canis Major is Sirius, also known as the 'big dog star'.
It's so bright in fact that the ancient Romans thought the star's light combined with the sun's energy gave us especially hot days. But the summer heat is not due to the added energy from a far away star. It's hot this time of year because the northern hemisphere is tilted toward the sun receiving more direct sunlight. Also, most of the summer a huge dome of high pressure sets up shop over the state of Texas, deflecting the rain and trapping in the heat.