In reply to jezzah:
I've been in the Himalaya right through the monsoon and it gets tricky as others have said, two real problems being landslides closing roads for a while [= delayed buses], and swollen streams. No doubt it depends where you are. Apart from being very wet I had quite a buzz being there though, never seen anything like it, the weather including clouds and rain were something else to say the least.
Sorry to sound a bit negative but that's my [limited] experience. Hope you have a great trip.