Temperatures in Alaska during the summer range from 55°F-80°F. Night times and early mornings are cooler, from the 40's - 50's. Late August and September departures could encounter cooler temperatures and slightly fewer hours of sunlight, as fall arrives early at these latitudes.
Alaska is our country's northern most state. It's above Canada and close to the North Pole. The cruise ships visit places with lots of ice, and you can take tours which give you the opportunity to go dog-sledding or trek across a glacier. With this said, you would expect it to be very cold in Alaska. It can be, but not really in the May - September Alaska Cruise Season.
Temperatures in Alaska vary based on the time of year and the port or city you are visiting. The weather off the ship is unpredictable, but here are the average daily high temperatures in Alaska major ports and cities: