Duas for rain

Invocation for when it rains

 Allaahumma sayyiban naafi'an

O Allah , (bring) beneficial rain clouds.

Reference: Al-Bukhari, cf. Al-Asqalani, Fathul-Bari 2/518.

Supplication after it rains

 Mutirnaa bifadhlillaahi wa rahmatihi.

It has rained by the bounty of Allah and His mercy

Reference: Al-Bukhari 1/205, Muslim 1/83.

Some 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.