Let us see the which words are used to mean rain.

Meaning of rain is 'mare' in common dialect & 'maḷe' in Brahmin dialect of Tuḷu language. The OldTuḷu one for rain was 'maḻe'. But in Tuḷu, the word mare or maḷe is very rarely used. The word barsa is highly used to mean rain in Tuḷu. Barsa is the Tadbhava form of Sanskrit word Varṣa. In Brahmin Tuḷu the word barṣa is used to mean rain. 

Its Tamizh cognate is maḻai & Malayaḷam cognate is maḻa. Kannaḍa cognate is maḷe which was maḻe in OldKannada. In Koḍava and Arebhashe languages the word maḷe is used to mean rain. 

In Telugu language the word either Varṣam or Vāna is used to mean rain.