See long range weather forecasts for the next 60 days for the Deep South Region. The Old Farmer's Almanac's scientifically-based, long range forecasts can be used to make more informed decisions about future plans that depend on the weather, from vacations and weddings to sporting events and outdoor activities.
Weather in Alaska in September. The average maximum daytime temperature in Alaska in September is a cool 13Â°C (55Â°F). There are usually 5 hours of bright sunshine each day, which represents 41% of the 13 hours of daylight. The average sea temperature in and around Alaska in September is 12Â°C (54Â°F).
Although the average daily temperatures throughout Southeast Alaska are in the 60s Fahrenheit in August, extreme highs near 90 and lows below 20 have been reported. Expect the temperature to fluctuate by 30 degrees or more in a single day regardless of when you cruise.