Knoxville Weather in September

The climate in Knoxville during September can be summarized as warm and damp.

September is in the fall / autumn in Knoxville and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 25°C (76°F), whilst at night 12°C (53°F) is normal.

On average September is the 4th wettest month of the year in Knoxville with around 103mm 4.1 inches of rain making it a damp time to visit. This rainfall is typically spread over 9 days, although this may vary considerably.

On the flip side this corresponds to an average of 8.5 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 Knoxville in September 2025.