Hadith 620
Chapter 33: It is recommended to pray Zuhr at the beginning of its time when there is no intense heat - كتاب الْمَسَاجِدِ وَمَوَاضِعِ الصَّلاَةِ
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، حَدَّثَنَا بِشْرُ بْنُ الْمُفَضَّلِ، عَنْ غَالِبٍ الْقَطَّانِ، عَنْ بَكْرِ بْنِ عَبْدِ اللَّهِ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ كُنَّا نُصَلِّي مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم فِي شِدَّةِ الْحَرِّ فَإِذَا لَمْ يَسْتَطِعْ أَحَدُنَا أَنْ يُمَكِّنَ جَبْهَتَهُ مِنَ الأَرْضِ بَسَطَ ثَوْبَهُ فَسَجَدَ عَلَيْهِ .
Anas b. Malik reported:
We used to say (the noonprayer) with the Messenger of Allah (ﷺ) in the intense heat, but when someone amongst us found it hard to place his forehead on the ground, he spread his cloth and prostrated on it.
Reference : Sahih Muslim 620
In-book reference : Book 5, Hadith 241
USC-MSA web (English) reference : Book 4, Hadith 1296