Du'a when it rains

Sheikh Jum’ān Lahmar ḥafidhahullāh said: When one sees [rain] clouds, he says: اللَّهُمَّ صَيِّبًا نَافِعًا "O Allah, [make it a] beneficial rain." And when rain falls, likewise he supplicates: اللَّهُمَّ صَيِّبًا نَافِعًا "O Allah, [make it a] beneficial rain."