It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Holy Prophet (peace and blessings be upon him) said: The intensity of heat is due to the effect of the heat of Hell, therefore when the heat is severe, perform the prayer after it has cooled down.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 7246