Right now in Philadelphia, the air is about 70°F, but the model estimates the asphalt under your dog's paws is closer to 96°F — a gap of roughly 26°F, because clear skies are pouring full sun onto every dark surface. That reading puts Philadelphia 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 9 hours left today, the pavement in Philadelphia is projected to top out near 96°F around 3 PM, when the air will be about 70°F — a 26°F gap between the forecast your weather app shows and the surface your dog walks on. The surface is already coming down, about 24°F over the next three hours, so waiting a little works in your favour here.
In an average October, Philadelphia sees highs around 69°F and overnight lows near 51°F. Those are forgiving numbers, but don't let them lull you — a sunny, still afternoon can still heat dark asphalt far above the air, especially for low-riding or short-coated dogs. For this month the normals suggest pavement rarely reaches unsafe temperatures here, but the seven-second hand test is still the final word on any given day.
Philadelphia loses its all-day safe window in 3 months of the year — June through August — and October is not one of them. The year peaks in July at an average high of 88°F against 43°F in January, a 45°F swing that decides how much of the day belongs to your dog.
The nearest place we track is Wilmington, DE, about 25 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 Philadelphia'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. Conditions in Philadelphia 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.