(4) باب الإِبْرَادِ بِالظُّهْرِ فِي شِدَّةِ الْحَرِّ
It was narrated that Mughirah bin Shu'bah said:
We were praying Zuhr with the Messenger of Allah at the time of intense heat (i.e., midday when the sun has just passed its zenith) and he said to us, "Wait for it to cool down before you pray, for intense heat is from the flaring up of the Hell-fire."
Reference: Sunan Ibn Majah 680
In-book reference: Book 2, Hadith 14
English translation: Vol. 1, Book 2, Hadith 680