lol I noticed that aswell. And also, a lot of my favourite songs have "rain" in it. or well, "ame", the japanese word for rain. XD
Buck-Tick - Rain (so creative!)
Merry - Sayonara Rain
T.M.Revolution - Get over the rain
Aya - Sining in the rain
B'z - It's raining
Craze - Rain noise
Buck-Tick - Nocturne Rain Song
Dead End - I can hear the rain
Gilles de Rais - Everlasting Rain
Glay - Rain (Tsk, noone had that? It's even produced/re-arranged by Yoshiki!
And you can SO hear it....)
Janne da Arc - Rainy ~ai no shirabe~ (I love that one!!!)
Luna Sea - Rain (Piano Version)
Mika Nakashima - Helpless Rain
Miz - In the rain
Pierrot - Acid Rain
Shizuka Kudo - Ice Rain
the briliant green - September Rain
the TRAX - Cold Rain
.
.
.
Okay, I left some out and it's THAT much? Now even I am surprised...XD;