Right now in Round Rock, the air is about 102°F, but the model estimates the asphalt under your dog's paws is closer to 129°F — a gap of roughly 27°F, because clear skies are pouring full sun onto every dark surface. That reading puts Round Rock in the danger range, where pavement can scald paw pads in under a minute. Air temperature alone would have told you none of this — the pavement, not the forecast, is what your dog actually stands on.
Across the 6 hours left today, the pavement in Round Rock is projected to top out near 129°F around 6 PM, when the air will be about 102°F — a 27°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, Round Rock sees highs around 96°F and overnight lows near 77°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.
Round Rock loses its all-day safe window in 6 months of the year — April through September — and August is one of them. The year peaks in August at an average high of 96°F against 60°F in January, a 36°F swing that decides how much of the day belongs to your dog.
The nearest place we track is Austin, about 17 miles away. That is close enough to move together in a heat wave but far enough that a passing cloud bank or a coastal breeze can put real distance between the two readings, so check Round Rock's own page rather than assuming.
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 Round Rock, 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.