Nantucket Weather in September

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

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

September is in the fall / autumn in Nantucket and is typically the 3rd warmest month of the year. Daytime maximum temperatures average around 21°C (70°F), whilst at night 14°C (58°F) is normal.

Nantucket weather averages (imperial / metric)
Daytime temperature 21.1°C 69.9°F
Nightly temperature 14.4°C 57.8°F
Average temperature 17.7°C 63.9°F
Daily sunshine 8.1 hrs
Avg rainfall 86 mm 3.4 ins
Rainy days 8 days
Sea temperature 18.4°C 65.2°F
Humidity 76%
Windspeed 15.5kph 10 mph

On average September is the 5th driest month of the year in Nantucket with around 86mm 3.4 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 8.1 hours of sunshine per day.

September temperatures in Nantucket

Nantucket average temperature in September

September rainfall

Nantucket average rain in September

September hourly sunshine

Nantucket 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 Nantucket 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

Nantucket weather stats

Nantucket weather statistics
Hottest month: July 24.3°C 75.7°F
Driest month: June 58mm 2.3ins
Sunniest month: October 7.4hrs
Coldest month: January 3.2°C 37.8°F
Wettest month: December 114mm 4.5ins
Map showing location of Nantucket (41.28346, -70.09946) Nantucket map pin © Google

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