The highest day temperature in September 2025 was 65°F. The lowest night temperature was 32°F. The average values for day and night temperatures during September were 49.4°F и 42.1°F respectivly.

The average sea surface temperature in September 2025 for Juneau was 53.8°F. The maximum and minimum values were 49.2°F and 59.2°F respectively.

Most of the days in September are gloomy but you can also expect sunny days.

Precipitation total in September for Juneau is 4.7 in. It makes september one of the most rainy months of the year.

The average wind speed in September is 5.2 mph.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Juneau in September is 3.1 hours.