Packing for a Caribbean cruise is pretty simple. (Bathing suit? Check!) Heading to Alaska is a whole other animal. Summertime here doesn't guarantee sunny skies and warm temperatures, and you'll be spending a lot of time outside, both on deck spotting pods of whales and hiking through the rainforests or on glaciers. So be prepared for all weather conditions — and have the right equipment for taking in all of the natural wonders. Here are the items you can't leave home without when you are heading to Alaska.