We didn't go that time of the year to Hawaii, but I just want to say, "hopefully" you will enjoy your trip. We went in January (Hawaii is known for little rain at a time.), and it decided to "rain on our parade." When I say rain, I mean gushers. If the wind wasn't blowing where you could not get in/out of the cruise doors, unless someone pulled on the other side, or when we were on land, we were walking in 2 - 3" of rain.
Enjoy your trip