Best island weather late march

hi all,
A quick question, which islands/areas have the best weather in late March? It's the only week we have to get away, and i'd prefer not to be rained out the whole time, but while various forums seem to say March is great in eg. Fiji, weather charts also seem to show high rainfall. I'm confused!
We're considering Fiji/Vanuatu (flying from Melbourne, so looking for somewhere closeish as we have such a short time).
Thanks