عَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ كَانَ إِذَا رَأَى نَاشِئًا مِنْ أُفُقٍ مِنْ آفَاقِ السَّمَاءِ تَرَكَ عَمَلَهُ وَإِنْ كَانَ فِي صَلَاتِهِ ثُمَّ يَقُولُ اللَّهُمَّ إِنِّي أَعُوذُ بِكَ مِنْ شَرِّ مَا فِيهِ فَإِنْ كَشَفَهُ اللَّهُ حَمِدَ اللَّهَ وَإِنْ مَطَرَتْ قَالَ اللَّهُمَّ صَيِّبًا نَافِعًا
It is narrated from Sayyida Aisha (may Allah be pleased with her) that when the Messenger of Allah (peace and blessings be upon him) saw an incomplete cloud in any part of the sky, he would leave his work, even if he was in prayer, and would begin to recite this supplication: "Allahumma inni a'udhu bika min sharri ma fihi" (O Allah! I seek refuge in You from the evil that is in this cloud). If Allah Almighty caused the cloud to disappear, the Prophet (peace and blessings be upon him) would praise Allah Almighty, and if it brought rain, the Prophet (peace and blessings be upon him) would supplicate: O Allah! Send beneficial rain.