Juneau Weather in September

The climate in Juneau during September can be summarized as cool and very wet.

September is in the fall / autumn in Juneau and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a cool 12°C (53°F), whilst at night 4°C (40°F) is normal.

On average September is the 2nd wettest month of the year in Juneau with around 210mm 8.3 inches of rain making it a very wet time to visit. This rainfall is typically spread over 19 days, although this may vary considerably.

On the flip side this corresponds to an average of 4.1 hours of sunshine per day.

The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Juneau in September 2025.