If the humidity is significantly higher than where you've been, you might want to leave it in the case for a couple of days to slow down the change for it.
Really high humidity (95%+ all the time) might be a problem, but Hawaii isn't usually that bad. Rapid changes in temperature and humidity are more of an issue than absolute amounts.
Concern about the humidity sort of implies you're not going to be in an air conditioned environment (which is something you can get away with in Hawaii better than most places). That means the humidity is going to fluctuate more than it's likely to in an air-conditioned house.
Keep an eye on the weather and talk to people who've been there a while. If the humidity rises and falls slowly (no more than 1% per hour), you'd probably do best to leave the violin out. If it changes rapidly (say, when a storm blows in), you'd do better to keep it in its case.