Mishkat al-Masabih 7 Fasting كتاب الصوم 108

وَعَنْ عَامِرِ بْنِ مَسْعُودٍ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «الْغَنِيمَةُ الْبَارِدَةُ الشِّتَاءِ» . رَوَاهُ أَحْمَدُ وَالتِّرْمِذِيُّ وَقَالَ: هَذَا حَدِيثٌ مُرْسل

‘Amir b. Mas’ud reported God’s messenger as saying, “Fasting in winter is booty gained without trouble.”* *Literally, ‘the cold booty.’ The idea is that in winter one does not suffer from hunger and thirst as in summer. Ahmad and Tirmidhi transmitted it, the latter saying this is a mursal tradition.