Abu Darda' reported: We were with the Messenger of Allah (ﷺ) on some of his journeys on an intensely hot day so much so that a person would place his hand on his head (in order to protect himself) against excessive heat, and none amongst us was fasting but the Messenger of Allah (ﷺ) and Abdullah b. Rawaha
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ الْقَعْنَبِيُّ، حَدَّثَنَا هِشَامُ بْنُ سَعْدٍ، عَنْ عُثْمَانَ بْنِ حَيَّانَ، الدِّمَشْقِيِّ عَنْ أُمِّ الدَّرْدَاءِ، قَالَتْ قَالَ أَبُو الدَّرْدَاءِ لَقَدْ رَأَيْتُنَا مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم فِي بَعْضِ أَسْفَارِهِ فِي يَوْمٍ شَدِيدِ الْحَرِّ حَتَّى إِنَّ الرَّجُلَ لَيَضَعُ يَدَهُ عَلَى رَأْسِهِ مِنْ شِدَّةِ الْحَرِّ وَمَا مِنَّا أَحَدٌ صَائِمٌ إِلاَّ رَسُولُ اللَّهِ صلى الله عليه وسلم وَعَبْدُ اللَّهِ بْنُ رَوَاحَةَ .
sunnah.com