Boston Weather in September

What's the weather like in Boston (Massachusetts) in September 2025?

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

September is in the fall / autumn in Boston and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 23°C (73°F), whilst at night 12°C (54°F) is normal.

Boston weather averages (imperial / metric)
Daytime temperature 22.6°C 72.7°F
Nightly temperature 12°C 53.6°F
Average temperature 17.3°C 63.1°F
Daily sunshine 8.3 hrs
Avg rainfall 82 mm 3.2 ins
Rainy days 9 days
Sea temperature 17.8°C 64.1°F
Humidity 73%
Windspeed 14.8kph 9 mph

On average September is the 3rd driest month of the year in Boston with around 82mm 3.2 inches of rain making it a a little 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 8.3 hours of sunshine per day.

September temperatures in Boston

Boston average temperature in September

September rainfall

Boston average rain in September

September hourly sunshine

Boston 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 Boston 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

Boston weather stats

Boston weather statistics
Hottest month: July 27.6°C 81.7°F
Driest month: July 75mm 3ins
Sunniest month: July 10.2hrs
Coldest month: January 1.2°C 34.2°F
Wettest month: November 111mm 4.4ins
Map showing location of Boston (42.35843, -71.05977) Boston map pin © Google

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