Somerville Weather in September

What's the weather like in Somerville (New Jersey) in September 2025?

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

September is in the fall / autumn in Somerville and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 25°C (77°F), whilst at night 12°C (53°F) is normal.

Somerville weather averages (imperial / metric)
Daytime temperature 24.9°C 76.8°F
Nightly temperature 11.9°C 53.4°F
Average temperature 18.4°C 65.1°F
Daily sunshine 7.7 hrs
Avg rainfall 106 mm 4.2 ins
Rainy days 8 days
Sea temperature 21°C 69.8°F
Humidity 71%
Windspeed 15.1kph 9 mph

On average September is the 4th wettest month of the year in Somerville with around 106mm 4.2 inches of rain making it a 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 7.7 hours of sunshine per day.

September temperatures in Somerville

Somerville average temperature in September

September rainfall

Somerville average rain in September

September hourly sunshine

Somerville average rain in September

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 Somerville in September 2025.

Other monthly averages

Best places to visit in September

UV index Best time to go?

Beta

Current (hourly) weather 15 day forecast

Somerville weather stats

Somerville weather statistics
Hottest month: July 29.4°C 84.9°F
Driest month: February 78mm 3.1ins
Sunniest month: August 9hrs
Coldest month: January 2.4°C 36.3°F
Wettest month: July 126mm 5ins
Map showing location of Somerville (40.57427, -74.60988) Somerville map pin © Google

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