كتاب الْمَسَاجِدِ وَمَوَاضِعِ الصَّلاَةِ
5  
The Book of Mosques and Places of Prayer
(32)
Chapter: The recommendation to delay Zuhr (until it has cooled down) in severe heat for one who finds it too hot in route to join the congregation
(32)
باب اسْتِحْبَابِ الإِبْرَادِ بِالظُّهْرِ فِي شِدَّةِ الْحَرِّ لِمَنْ يَمْضِي إِلَى جَمَاعَةٍ وَيَنَالُهُ الْحَرُّ فِي طَرِيقِهِ
Sahih Muslim 617 c

Abu Huraira reported that the Messenger of Allah (ﷺ) said:

The Fire said to the Lord: O Lord! some parts of mine have consumed the others, so allow me to exhale (in order to find some relief from this congestion). It was granted permission to take two exhalations, one exhalation during the winter and the other exhalation during the summer So whatever you perceive in the form of intense cold or hurting cold is from the exhalation of Hell. And whatever you perceive in the form of extreme heat or intense beat is from the exhalation of Hell.
وَحَدَّثَنِي حَرْمَلَةُ بْنُ يَحْيَى، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ وَهْبٍ، أَخْبَرَنَا حَيْوَةُ، قَالَ حَدَّثَنِي يَزِيدُ بْنُ عَبْدِ اللَّهِ بْنِ أُسَامَةَ بْنِ الْهَادِ، عَنْ مُحَمَّدِ بْنِ إِبْرَاهِيمَ، عَنْ أَبِي سَلَمَةَ، عَنْ أَبِي هُرَيْرَةَ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم قَالَ ‏ "‏ قَالَتِ النَّارُ رَبِّ أَكَلَ بَعْضِي بَعْضًا فَأْذَنْ لِي أَتَنَفَّسْ ‏.‏ فَأَذِنَ لَهَا بِنَفَسَيْنِ نَفَسٍ فِي الشِّتَاءِ وَنَفَسٍ فِي الصَّيْفِ فَمَا وَجَدْتُمْ مِنْ بَرْدٍ أَوْ زَمْهَرِيرٍ فَمِنْ نَفَسِ جَهَنَّمَ وَمَا وَجَدْتُمْ مِنْ حَرٍّ أَوْ حَرُورٍ فَمِنْ نَفَسِ جَهَنَّمَ ‏"‏ ‏.‏
Reference : Sahih Muslim 617c
In-book reference : Book 5, Hadith 237
USC-MSA web (English) reference : Book 4, Hadith 1292
  (deprecated numbering scheme)