وَعَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ
قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «صُومُوا لِرُؤْيَتِهِ وَأَفْطِرُوا لِرُؤْيَتِهِ فَإِنْ غم عَلَيْكُم فَأَكْمِلُوا عِدَّةَ شَعْبَانَ ثَلَاثِينَ»
Abu Hurayrah reported God’s messenger as saying, “Fast when you see it and break your fast when you see it, and if the weather is cloudy treat Shaban as having thirty days.”
Mishkat al-Masabih 1880, Book 8, Fasting, Hadith 14. 1 min read