Sayyidah Asma' (may Allah be pleased with her) says: We broke our fast in the time of the Messenger of Allah (peace and blessings be upon him) on a cloudy day, then the sun appeared. (The narrator says:) I said to Hisham: "Were they then ordered to make it up?" He said: "That was unavoidable."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8011