Right now in Joliet, the air is about 80°F, but the model estimates the asphalt under your dog's paws is closer to 119°F — a gap of roughly 39°F, because heavy cloud cover is taking some of the edge off the direct sun. That reading puts Joliet in the caution range, where short, shade-hugging walks are the most a paw should take. Air temperature alone would have told you none of this — the pavement, not the forecast, is what your dog actually stands on.
Across the 10 hours left today, the pavement in Joliet is projected to top out near 119°F around 2 PM, when the air will be about 80°F — a 39°F gap between the forecast your weather app shows and the surface your dog walks on. The surface is already coming down, about 12°F over the next three hours, so waiting a little works in your favour here.
In an average August, Joliet sees highs around 82°F and overnight lows near 64°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.
Joliet 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 83°F against 33°F in January, a 51°F swing that decides how much of the day belongs to your dog.
The nearest place we track is Naperville, about 18 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 Joliet'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 Joliet, 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.