Zaid bin Wahb (may Allah have mercy on him) says that once we were returning from a funeral when we passed by Abu Dharr (may Allah be pleased with him). He said: Once we were on a journey with the Prophet Muhammad (peace and blessings be upon him). When the muezzin intended to give the adhan for Zuhr prayer, the Prophet (peace and blessings be upon him) said to him, "Give the adhan after cooling down." This happened two or three times, until we began to see the shade of the mounds. The Prophet (peace and blessings be upon him) also said: "The intensity of heat is from the effect of the heat of Hell, so when the heat is severe, perform the prayer after cooling down."