Right now in Richardson, the air is about 103°F, but the model estimates the asphalt under your dog's paws is closer to 129°F — a gap of roughly 26°F, because clear skies are pouring full sun onto every dark surface. That reading puts Richardson in the danger range, where pavement can scald paw pads in under a minute. Humidity is nudging the human "feels-like" to about 106°F, which matters for your dog too: muggy air makes it harder for a panting dog to shed heat, so treat a borderline reading as the hotter of the two.
Across the 6 hours left today, the pavement in Richardson is projected to top out near 129°F around 6 PM, when the air will be about 103°F — a 25°F gap between the forecast your weather app shows and the surface your dog walks on. The surface is already coming down, about 30°F over the next three hours, so waiting a little works in your favour here.
In an average August, Richardson sees highs around 95°F and overnight lows near 78°F. At highs like that, sun-baked pavement can easily top 120–130°F by early afternoon, so the walkable hours cluster around dawn and after sunset. As a seasonal rule of thumb, the safest windows are before about 9:00 AM and after about 6:00 PM.
Richardson loses its all-day safe window in 5 months of the year — May through September — and August is one of them. The year peaks in August at an average high of 95°F against 56°F in January, a 40°F swing that decides how much of the day belongs to your dog.
Richardson sits about 5 miles from Plano, close enough that the two usually run within a degree or two of each other — if your walk crosses between them, either page answers the question. Street-level conditions still differ more than city-level ones do: a shaded side street and an open parking lot half a block apart can be twenty degrees apart underfoot.
Whatever the number says, confirm it with your hand: press the back of it flat on the pavement for seven seconds. If you can't hold it there, neither can your dog. On a day reading this warm in Richardson, flat-faced breeds like pugs and bulldogs, plus seniors and young puppies with thinner pads, should sit out the heat entirely — subtract about 10°F from any safe threshold for them. If you must cross hot ground, protective booties or a quick coat of paw wax are the only real barrier between paw pads and the asphalt.