We have sailed Alaska in late May, June, August and September - shorts to hike in Skagway, sunny and lovely on the pool deck one cruise and rainy and windy on another. We only wore coats on the day we were outside watching the glacier. Other than that it was layers of tee shirt, long sleeve wool tee, fleece/vest if needed and a raincoat was the top layer. The scenery and the wildlife are so interesting - nothing like Caribbean beach days.