We set out with Messenger of Allah ﷺ on one of his journeys on a very hot day, and it was so hot that one had to put his hand over his head because of the severity of heat. None of us was fasting except the Prophet and Ibn Rawaha.  

خَرَجْنَا مَعَ النَّبِيِّ ﷺ فِي بَعْضِ أَسْفَارِهِ فِي يَوْمٍ حَارٍّ حَتَّى يَضَعَ الرَّجُلُ يَدَهُ عَلَى رَأْسِهِ مِنْ شِدَّةِ الْحَرِّ وَمَا فِينَا صَائِمٌ إِلاَّ مَا كَانَ مِنَ النَّبِيِّ ﷺ وَابْنِ رَوَاحَةَ