Tlaloc, the Aztec Rain God

Tláloc is the god of rain in Aztec religion. He was also a deity of earthly fertility and water, worshipped as a giver of life and sustenance. He was feared, but not maliciously, for his power over hail, thunder, lightning, and even rain. He is also associated with caves, springs, and mountains, most specifically the sacred mountain where he was believed to reside. His followers were one of the oldest and most universal in ancient Mexico. (Paraphrased from Wikipedia)