Hiya

We stayed at the Mount Lavinia for a couple of nights in June last year. You can read my review at http://www.holidaytruths.co.uk/reviews/sri-lanka/dehiwala-mount-lavinia/mount-lavinia-hotel/

It was monsoon season when we went but we only had 10 mins of heavy monsoon rain on the last day of our holiday and some light rain in Kandy. It was quite cloudy though, which fooled me in to thinking that the sun wasn't that strong, resulting in a very bad case of sunburn on the first day. So make sure you use plenty of sun-tan lotion.

If you have any other questions then please feel free to ask.