Norwegian is the only cruise line to base ships in Hawaii at this time and they are expanding this greatly in the near future.
Many other lines divert ships to (or from )Hawaii on the way to or from their season in Alaska. These are usually 11 to 14 day cruises that include 4 or 5 days at sea getting to (or from) Hawaii.
Any good travel agent can cut through this research for you.
I would add that my dearly beloved and I have been to Hawaii at all diferent times of the year. It's always about the same, except in summer, you're more likely to encounter tropical storms. That's no big deal, either. It's so warm that people don't stop what they're doing because it rains. Once in Honolulu, we were asked to bring in the balcony furniture because of a "major storm" which turned out to be just a hard rain. Another time, we always managed to be ahead of the storm.
Guess you just have to learn to take things in stride when you travel. Unless you get sick; that's different.