Question: Dear Shaykh, please give us a ruling on the Sawm (fasting) of Ramadaan, because people are still differing over this in our African countries. Some of them perform the Sawm on seeing the crescent moon and break their Sawm on seeing it, acting in accordance with the saying of the Prophet (peace be upon him), “When you see it (the new moon of Ramadaan) fast, and when you see it (the new moon of Shawwaal) stop fasting; but if the clouds obstruct your sighting of the new moon, then calculate it (thirty days).” (Agreed upon by Al-Bukhaaree and Muslim) Some of them perform the Sawm before seeing it and their Sawm coincides with the day the new moon of Ramadaan appears, even though this contradicts the literal meaning of the Hadeeth. We are confused about this matter, would you advise us?
Answer: Anyone who fasts on the 30th of Sha‘baan, without the confirmed sighting of the new moon of Ramadaan prescribed by Sharee‘ah (Islaamic law), and their Sawm coincides with the first day of Ramadaan, it will not count for them as validly sufficient Sawm, as they did not base their Sawm on the Islaamic basis and also because that is the Day of Doubt. The authentic Sunnah gave evidence for the prohibition of fasting on that day, so anyone who did this must make up for that day... read more here.