Is there a set number of days for breaking the fast while traveling?
Machine translationRead the Arabic original
The questioner : We would also like to know if there is a set number of days for breaking the fast while traveling?
The Shaykh : If a person intends to travel or stay in a city other than his own, for example, for more than five or six days, he may break his fast. This is because the Messenger (peace and blessings be upon him), when he conquered Makkah, entered it in Ramadan on the twentieth of the month and did not fast the rest of the month, as is authentic. It is authentic that he did not fast the rest of the month, according to the hadith of Ibn 'Abbas (may Allah be pleased with them both) as narrated by al-Bukhari from him. He remained there for nine or ten days after that, so the Messenger (peace and blessings be upon him) stayed in Makkah for nineteen days, shortening the prayer and breaking his fast in Ramadan.
The Shaykh : If a person intends to travel or stay in a city other than his own, for example, for more than five or six days, he may break his fast. This is because the Messenger (peace and blessings be upon him), when he conquered Makkah, entered it in Ramadan on the twentieth of the month and did not fast the rest of the month, as is authentic. It is authentic that he did not fast the rest of the month, according to the hadith of Ibn 'Abbas (may Allah be pleased with them both) as narrated by al-Bukhari from him. He remained there for nine or ten days after that, so the Messenger (peace and blessings be upon him) stayed in Makkah for nineteen days, shortening the prayer and breaking his fast in Ramadan.
Source
ابن العثيمين - فتاوى الصيام — archive.org (24:08)
The Arabic text is a machine transcription of the audio recording.