Hi,
I've been to the Maldives 3 times with number 4 coming up in a few months. We stay at an island very near Vilamenhoo (only a couple of miles away so they will have the same weather systems which vary greatly in the Maldives.
Best time to go is December to March. It is hot all year round ) 28-32 degrees) but those are the months with the least amount of rain. We been twice in December and once in May (which is supposed to be one the the wettest months )and although we did have more rain it was mostly at night and the drop in price that we paid certainly made up for it compared to peak season rates.
The Maldives is all about rest and peace and quiet so don't expect there to be a lot to do. At night your island with organise some entertainment possibly twice a week (a band and some local dancers usually) but the rest of the time it's pretty quiet. As for the daytime the underwater wildlife should keep you pretty much amused but the islands also organise 1/2 days trips to a couple of local islands once a week. Don't expect the number or variety of trips you get in the Caribbean. You'll get trips such as night fishing or sunset or sunrise trips to watch Dolphins in the wild but to be honest thats about it.
Hope that helps
Tracy