Sahih Muslim Book - 5, Hadith - 1402

وَحَدَّثَنِى إِسْحَاقُ بْنُ مُوسَى الأَنْصَارِىُّ حَدَّثَنَا مَعْنٌ حَدَّثَنَا مَالِكٌ عَنْ عَبْدِ اللَّهِ بْنِ يَزِيدَ مَوْلَى الأَسْوَدِ بْنِ سُفْيَانَ عَنْ أَبِى سَلَمَةَ بْنِ عَبْدِ الرَّحْمَنِ وَمُحَمَّدِ بْنِ عَبْدِ الرَّحْمَنِ بْنِ ثَوْبَانَ عَنْ أَبِى هُرَيْرَةَ أَنَّ رَسُولَ اللَّهِ -صلى الله عليه وسلم- قَالَ « إِذَا كَانَ الْحَرُّ فَأَبْرِدُوا عَنِ الصَّلاَةِ فَإِنَّ شِدَّةَ الْحَرِّ مِنْ فَيْحِ جَهَنَّمَ ». وَذَكَرَ « أَنَّ النَّارَ اشْتَكَتْ إِلَى رَبِّهَا فَأَذِنَ لَهَا فِى كُلِّ عَامٍ بِنَفَسَيْنِ نَفَسٍ فِى الشِّتَاءِ وَنَفَسٍ فِى الصَّيْفِ ».

It was narrated from Abu Hurairah that the Messenger of Allah (s.a.w) said: "When it is hot, wait for it to cool down somewhat before praying, for the intense heat is an exhalation from Hell." And he mentioned: "The Fire complained to its Lord, so He gave it permission to breathe out twice each year, once in the winter and once in the summer."