Okay, because I got to thinking about the sound of rain on a window, and I like to use the internet for all things, I got to searching for "words that describe rain falling on a window" and here's what I found. All good ideas!

I heard the rain thrumming on the roof.

I heard the rain pelting the window.

I heard the rain battering the roof.

I heard the rain drumming on the window.

Or, if you like the drumming idea and want to get a bit more literary about it, how about:

The rain beat a gentle / violent / solemn tattoo on the roof.






Queen Norma Jean