Unfortunately the rain description might not be enough :( rain in Indian film songs has come to be a cliche concept. perhaps if you could give more descriptions, there might someone here who might be able to zero in on the song.

This one is a personal favorite of mine. Its from the movie paiyya and the song features rain and its a catchy number! :)

http://www.youtube.com/watch?v=UIAGnkr-1rw