Answer: The Prophet—may peace and blessings be upon him—said, “Fast when you see it and end the fast when you see it.” He thus linked the obligation of fasting to the sighting of the crescent, and—according to the sounder of the two scholarly opinions—sighting varies from one horizon to another. There is no doubt that the horizon in Algeria differs from that of the Kingdom of Saudi Arabia. Accordingly, every person must begin and end the fast with the people of the region and country in which he lives when they sight the crescent. Your ruling is the same as that of the Muslims among whom you reside, wherever that may be—whether in Algeria or elsewhere; you fast with them and you break the fast with them.

Fasting while Traveling from One Country to Another
Question: A person travels abroad for study, and—as is well known—the local time there differs from that of his homeland. If the hours of fasting increase or decrease because of the time difference, does that affect his fast or not? Please advise, and may Allah bless you.

Answer: Whoever travels to a land other than his own and finds that its time zone differs from that of his homeland is governed by the rulings of the land to which he has traveled. He should fast and break his fast according to that country: he begins the fast when dawn breaks there and ends it when the sun sets there, paying no attention to the timetable of his homeland, for he has left it. Every locale has its own ruling; therefore, when a person is in a particular land, he follows the rulings of that land, not those of the country from which he came.