I learned some years ago that black basenjis get much hotter than reds, that black coat absorbs the sun. My 14 year old red girl was going strong when the 1 1/2 year old black boy drug us under a tree and threw himself down in the cool grass, panting.
I always take water along, and try and make sure they aren't overheated, but I see so many people out running with a dog (here in Florida) with no water for the dog. It makes me sad and angry!
Also among red basenjis, some can stand the heat much better than others. One of my girls, her son, and also her mother wilt very easily in the heat. They pant easily, and like to seek out the shade quickly.