Yes, I will go barefoot in summer even if the ground is hot. Most sidewalk is less hot--even gray concrete and red brick tiles. Most asphalt is very hot--especially smooth blacktop and black brick tiles.
Hot enough, my feet will definitely respond by burning. Standing burns faster than walking. Sometimes the burning will not get any more, and sometimes the burning will continue to increase. I have found that if the feet start tingling and stay tingling from that much burning, then it is necessary to cool the feet almost immediately. If there isn't a shade patch, then staying on the edges of the feet or lifting one foot in the air might be enough to cool the feet from tingling. If the tingling becomes a watery pinching sensation, part of the foot is already blistered.
Then again, since burning of the feet more and more is a necessary part of increasing heat tolerance, pushing the feet sometimes to blisters is considered normal, until the feet no longer blister from that extra hot heat.