Right now in South Boston, the air is about 65°F, but the model estimates the asphalt under your dog's paws is closer to 65°F — the surface and air have nearly converged because heavy cloud cover is taking some of the edge off the direct sun. That reading puts South Boston 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 17 hours left today, the pavement in South Boston is projected to top out near 91°F around 5 PM, when the air will be about 70°F — a 21°F gap between the forecast your weather app shows and the surface your dog walks on. The surface is still gaining — up about 4°F over the next three hours — so a walk taken now is cooler than the same walk later this afternoon.
In an average August, South Boston sees highs around 80°F and overnight lows near 65°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 12:00 PM and after about 3:00 PM.
South Boston 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 82°F against 38°F in January, a 44°F swing that decides how much of the day belongs to your dog.
South Boston sits about 2 miles from Boston, 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 South Boston 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.