Dua in the Istisqa sermon — send us rain
اللّهُـمَّ أَغِثْنَـا، اللّهُـمَّ أَغِثْنَـا، اللّهُـمَّ أَغِثْنَـا
اللّهُـمَّ أَغِثْنَـا، اللّهُـمَّ أَغِثْنَـا، اللّهُـمَّ أَغِثْنَـا
Allahumma aghithna, Allahumma aghithna, Allahumma aghithna
Translation
O Allah, send us rain. O Allah, send us rain. O Allah, send us rain.
When to recite
Recited three times in the Istisqa (rain prayer) sermon when seeking rain during drought. The Prophet raised his hands high and repeated this three times on the pulpit.
Source / Reference
Al-Bukhari 1/224, Muslim 2/612