Mattapoisett Weather in September

The climate in Mattapoisett during September can be summarized as mild and a little damp.

September is in the fall / autumn in Mattapoisett and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 22°C (72°F), whilst at night 13°C (56°F) is normal.

On average September is the 4th driest month of the year in Mattapoisett with around 90mm 3.5 inches of rain making it a a little damp time to visit. This rainfall is typically spread over 8 days, although this may vary considerably.

On the flip side this corresponds to an average of 8.2 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 Mattapoisett in September 2025.