اَللَّهُمَّ اسْقِنَا غَيْثًا مُغِيثًا مَرِيئًا مَرِيعًا نَافِعًا غَيْرَ ضَارٍّ، عَاجِلًا غَيْرَ آجِلٍ
Transliteration
Allahummasqina ghaythan mughithan mari'an mari'an nafi'an ghayra darrin, 'ajilan ghayra ajil
English meaning
O Allah, send us beneficial rain — abundant, healthy, profitable, and not harmful, soon and not delayed.
When is it recited?
In times of drought.
Source
Abu Dawud, Istisqa' 2