How about Tonga? http://www.tongasailing.com/fleet.htm
Vava'u and surrounds is good cruising. a lot like the Virgin Islands in the Caribbean. Expensive. Yes.
January and February is cyclone season. Forget rain, think hurricanes. but, as in the Caribbean, there aren't a lot, and I don't think Tonga has been hit with one in several years. Not sure about the rain. Cruisers tend to not be there during cyclone season, and the locals just take whatever comes along.
I know, I'm not very helpful here, but maybe somebody else can come along and fill in the blanks.