Ruling 1544 — Fasting (Ṣawm)

There is no problem if someone intentionally does not make the intention to fast until near ẓuhr for an obligatory fast that has not been assigned for a particular day, such as a fast for kaffārah. If a person decides not to fast or is indecisive as to whether he should fast or not, in the event that he has not done anything that invalidates a fast, he can make the intention before ẓuhr to fast and his fast will be valid.