´It was narrated that Abu Hurairah said:` "the Messenger of Allah said: 'Fast when you see it and stop fasting when you see it, and if it is obscured from you (too cloudy), then count it as thirty (days). "'
Hadith ReferenceSunan an-Nasa'i / The Book of Fasting / Hadith: 2119
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:متفق عليه