The 6am pavement thing got me too, but here's the part nobody talks about: it's not just the air temp, it's the sun angle. In Phoenix in June the sun is already high enough by 6:15 that dark asphalt has been soaking up rays since 5:30, so the surface runs way hotter than the air. I grabbed one of those cheap infrared thermometers off Amazon for like 15 bucks and started checking surfaces before we head out. Black asphalt on my street hit 138 degrees at 6am in July, while the dirt shoulder next to it was only 89. Concrete was around 105. That 7 second rule people repeat is decent but it varies a ton by surface color and shade, so the thermometer takes the guesswork out. Makes you realize how many dogs are out there limping on hot blacktop while their owners have no clue.