Right now in Arlington, the air is about 78°F, but the model estimates the asphalt under your dog's paws is closer to 99°F — a gap of roughly 21°F, because a mix of sun and cloud is still loading heat into the asphalt. That reading puts Arlington in the clear for an ordinary walk. Air temperature alone would have told you none of this — the pavement, not the forecast, is what your dog actually stands on.
Across the 7 hours left today, the pavement in Arlington is projected to top out near 99°F around 5 PM, when the air will be about 78°F — a 21°F gap between the forecast your weather app shows and the surface your dog walks on. The surface is already coming down, about 20°F over the next three hours, so waiting a little works in your favour here.
In an average August, Arlington sees highs around 86°F and overnight lows near 69°F. Even at those moderate highs, a dark surface in direct sun can run 40–60°F hotter than the air, which is enough to tip midday walks into the caution range. As a seasonal rule of thumb, the safest windows are before about 11:00 AM and after about 4:00 PM.
Arlington loses its all-day safe window in 3 months of the year — June through August — and August is one of them. The year peaks in July at an average high of 89°F against 45°F in January, a 44°F swing that decides how much of the day belongs to your dog.
Arlington sits about 4 miles from Washington, 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. Conditions in Arlington are on the gentler side right now, but keep the same habits: water before and after, grass over asphalt, and a close eye on flat-faced breeds, seniors, and puppies, who overheat and burn sooner than a healthy adult dog.