Messenger of Allah said: "In very hot weather, delay the (Zuhr) prayer until it becomes (a bit) cooler, because the severity of heat is from the raging of the Hell."  

قَالَ رَسُولُ اللَّهِ ﷺ إِذَا اشْتَدَّ الْحَرُّ فَأَبْرِدُوا عَنِ الصَّلاَةِ فَإِنَّ شِدَّةَ الْحَرِّ مِنْ فَيْحِ جَهَنَّمَ قَالَ وَفِي الْبَابِ عَنْ أَبِي سَعِيدٍ وَأَبِي ذَرٍّ وَابْنِ عُمَرَ وَالْمُغِيرَةِ وَالْقَاسِمِ بْنِ صَفْوَانَ عَنْ أَبِيهِ وَأَبِي مُوسَى وَابْنِ عَبَّاسٍ وَأَنَسٍ قَالَ وَرُوِيَ عَنْ عُمَرَ عَنِ النَّبِيِّ ﷺ فِي هَذَا وَلاَ يَصِحُّ  

"Messenger of Allah was on a journey and Bilal was with him. So he wanted to call for the prayer, but he (the Prophet) said: 'Let it get cooler.' Then he wanted to call for the prayer, so Messenger of Allah said: 'Let it get to the cooler time of Zuhr.'" He (i.e., Abu Dharr) said: "Until we saw the shadows of the hillocks, then he commanded that the Iqamah be called and then led the people in prayer. Messenger of Allah said: 'The severity of heat is from the raging of Hell, so wait until it becomes cooler for the (Zuhr) prayer.'"  

أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ فِي سَفَرٍ وَمَعَهُ بِلاَلٌ فَأَرَادَ بِلاَلٌ أَنْ يُقِيمَ فَقَالَ أَبْرِدْ ثُمَّ أَرَادَ أَنْ يُقِيمَ فَقَالَ رَسُولُ اللَّهِ ﷺ أَبْرِدْ فِي الظُّهْرِ قَالَ حَتَّى رَأَيْنَا فَىْءَ التُّلُولِ ثُمَّ أَقَامَ فَصَلَّى فَقَالَ رَسُولُ اللَّهِ ﷺ إِنَّ شِدَّةَ الْحَرِّ مِنْ فَيْحِ جَهَنَّمَ فَأَبْرِدُوا عَنِ الصَّلاَةِ