Fasting: Timing the Start of the Two-Month Kaffarah Fast
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 1632
Someone who wants to fast for two consecutive months for the kaffārah of a fast of the month of Ramadan must not start at a time when he knows a day on which fasting is unlawful – such as Eid al-Aḍḥā – will fall within the one month and one day period, nor must he fast at a time when he knows a day on which fasting is obligatory (such as a day of the month of Ramadan) will fall within that period.