Dua'a (Invocations for Rain)

Allaahumma 'asqinaa ghaythan mugheethan maree'an maree'an, naafi'an ghayradhaarrin, 'aajilan ghayra 'aajilin.
O Allah, shower upon us abundant rain, beneficial not harmful, swiftly and not delayed.

Reference: Abu Dawud 1/303. See also Al-Albani SahihAbu Dawud 1/216

Allaahumma 'aghithnaa, Allaahumma 'aghithnaa, Allaahumma 'aghithnaa.
O Allah , send us rain . O Allah , send us rain . O Allah , send us rain.

Reference: Al-Bukhari 1/224, Muslim 2/613

Allaahum-masqi 'ibaadaka, wa bahaa'imaka, wanshur rahmataka, wa 'ahyi baladakal-mayyita.
O Allah , give water to Your slaves , and Your livestock , and spread Your mercy , and revive Your dead land.
Reference: Abu Dawud 1/305. Al-Albani graded it good in Sahih Abu Dawud 1/218.
[Fortress of the Muslim]