We were on the Eurodam to Alaska last week and wore everything from t-shirts and shorts to sweatshirts and stocking hats. We brought raincoats, but fortunately never needed them as we had good weather. I would skip the winter coat, but definitely bring sweatshirts, hoodies, and hats. I would also still bring a raincoat/windbreaker. We lucked out this time, but have needed them in Alaska on previous trips.