We went Sept. 8 last year & the weather was a little cool but only had sprinkles the day we were at Skagway. Some days we only wore sweatshirts, but had no t-shirt weather. Expect chilly days, but maybe you'll be fortunate to get a few sunny days also. Have a fun cruise! We did the train ride. If it's a nice day, you get some great views. But it is a bit long.