It is the period from July 3 to August 11 that is traditionally known as the "dog days of summer." No, it's not because the pavement is hot enough to fry a dog's brain. It has to do with Sirius, "The Dog Star," which is a feature of Canus Major, "The Big Dog" (as opposed to Canus Minor, "The Little Dog"). At that time of year, Sirius rises and sets along with the Sun. That and the star's brightness in the night sky are why the ancient Romans believed they got heat from it. These days, we know it comes from the tilt of the Earth's axis. Read more about it at... About.com.
Just the same, right about now you probably could fry a dog's brain in the Nation's capital -- not that I'd recommend it. With temperatures topping 100 all this week, your own brain probably wouldn't fare much better. Meanwhile, they've got me working for a living this week, so there will be some new topics later in the day.
Till then, stay tuned, and stay in touch.