What is the ruling regarding someone who breaks their fast in one country, then travels to another country, and the number of days they will fast becomes unclear to them, so should they fast 31 or 32 days, even though the hadith states: "Complete thirty days"?

Scholars differed regarding one who travels to a country where his breaking of the fast is delayed. The most correct view among the Shafi'is, which was also preferred by العلامة العثيمين (Allamah Al-Uthaymeen), is that he is obligated to fast with them even if it exceeds thirty days. This is because by moving to their country, he becomes one of them, and their ruling applies to him. This is supported by Ibn Abbas's command to Kurayb in this regard, and by the Prophet's (peace be upon him) saying: "The fast is on the day the people fast, and the breaking of the fast is on the day the people break their fast."

If he believes that the sighting in one country obligates all countries, or if he imitates one who issues such a fatwa, or if he holds the view of differing moonrises but chooses to act upon the second opinion, which is that he does not exceed thirty days, then he should break his fast discreetly.

However, if he moves from a country where the sighting of the month was delayed to a country where the sighting of the month occurred earlier, then he should break his fast with them and make up for the Ramadan days he missed.