Ruling on Completing Shaʿbān Thirty Days if the Crescent is Blocked on the Thirtieth Night
What is the ruling if the crescent of Ramadan is obscured and not seen on the thirtieth night of Shaʿbān?
If the crescent is obscured on the thirtieth night of Shaʿbān, it is obligatory to complete Shaʿbān as thirty days. The day of doubt is fasted only as a voluntary fast; fasting it for another obligatory fast is disliked, and fasting it decisively as Ramadan is prohibitively disliked.
It is obligatory to complete Shaʿbān thirty days if clouds or dust obstruct sighting the crescent on the thirtieth night. Fasting the day of doubt as a precaution for Ramadan is disliked and does not count for it, while fasting it by habit, voluntarily, or as a make-up fast is permissible.
If clouds or dust obstruct sighting the crescent on the thirtieth night of Shaʿbān, completing the month as thirty days is obligatory, based on the Prophet's saying: "If it is obscured, then estimate for it."
If clouds or dust obstruct the thirtieth night of Shaʿbān, it is obligatory to fast it with the intention of Ramadan out of precaution, and completing Shaʿbān as thirty days is not obligatory.