hadith

 Sahih Bukhari  صحیح بخاری

Hadith # 534

Translation:

Narrated Abu Hurairah (RA) and Abdullah bin Umar (RA): Allahs Apostle ﷺ said, "If it is very hot, then pray the Zuhr prayer when it becomes (a bit) cooler, as the severity of the heat is from the raging of the Hell-fire."