I only have one type of evening dress, fairly all weather and I always take a shawl, jacket or sweater with me. I learned the hard way on a Carnival cruise. My formalwear in those days was pretty flimsy. After the first formal night when I literally turned blue with cold, I ate in the alternative dining room the other formal night. That way I could stay casual and in warm clothes. People don't seem to dress as elaborately in Alaska as they do in the Caribbean.