September weather forecast
Nantucket, MA

Share
Beautiful homes built on the water overlooking the boats on the water below, in Nantucket, Massachusetts
Beautiful homes built on the water overlooking the boats on the water below, in Nantucket, Massachusetts

Weather in September

September brings the onset of fall in Nantucket, demonstrating a decrease in the average high temperature down to 67.6°F (19.8°C). However, the drop in temperature does not dampen local spirits or curtail outdoor activities. The beauty of fall foliage begins to show this month, giving the city a unique character. Rainfall picks up gradually in comparison to the summer months, and the sunshine hours begin to reduce. September provides a gentler, yet still warm, weather environment, perfect for exploring Nantucket's leaf-peeping routes.

Temperature

The transition from August to September in Nantucket sees average high-temperatures adjusting to an enjoyable 67.6°F (19.8°C), from a not significantly different 72.1°F (22.3°C). Nantucket reports an average low temperature of 63.9°F (17.7°C) in September, a minor decrease from the day's highs.

Humidity

The average relative humidity in September is 80%.

Rainfall

In Nantucket, in September, it is raining for 11.7 days, with typically 2.2" (56mm) of accumulated precipitation. Throughout the year, there are 153 rainfall days, and 26.61" (676mm) of precipitation is accumulated.

Snowfall

In Nantucket, snow does not fall in April through October.

Ocean temperature

In Nantucket, in September, the average water temperature is 65.1°F (18.4°C).
Note: The majority find it unenjoyable to swim in 65.1°F (18.4°C). Breathing becomes tougher as the water temperature descends under 69.8°F (21°C).

Daylight

The average length of the day in September in Nantucket is 12h and 28min.
On the first day of the month, sunrise is at 6:07 am and sunset at 7:12 pm. On the last day of September, sunrise is at 6:36 am and sunset at 6:23 pm EDT.

Sunshine

In September, the average sunshine is 8.6h.

UV index

The average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for the average person.
Note: In September, the average maximum UV index of 5 translates into the following recommendations:
Guard yourself - Avoiding sunburn is suggested. The Sun's UV radiation is especially harmful around midday, so reduce exposure and stay safe. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure.
[Resources]

Frequently asked questions

What are September temperatures in Nantucket?

During September, Nantucket experiences an average high-temperature of 67.6°F (19.8°C) and a low-temperature of 63.9°F (17.7°C).

What is the average humidity in September in Nantucket?

In Nantucket, the average relative humidity in September is 80%.

How many days does it rain in September in Nantucket?

In September, in Nantucket, the rain falls for 11.7 days. Throughout September, 2.2" (56mm) of precipitation is accumulated.

When it does not snow in Nantucket?

April through October are months without snowfall in Nantucket, Massachusetts.

How cold is the water in September in Nantucket?

In Nantucket, Massachusetts, in September, the average water temperature is 65.1°F (18.4°C). Swimming in 65.1°F (18.4°C) is not enjoyable for the majority. Controlling breathing becomes progressively more difficult as surface water temperature decreases below 69.8°F (21°C).

What is the average length of the day in September in Nantucket?

The average day length in September in Nantucket, Massachusetts, is 12h and 28min.

When is the sunrise / sunset in September in Nantucket?

On the first day of September, sunrise is at 6:07 am and sunset at 7:12 pm. On the last day of the month, sunrise is at 6:36 am and sunset at 6:23 pm EDT.

How many hours of sunshine does Nantucket have in September?

In Nantucket, the average sunshine duration in September is 8.6h.

What is the UV index intensity in September in Nantucket?

In Nantucket, Massachusetts, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium health risk from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Nantucket, MA

Average temperature in September - Nantucket, MA
  • Average high temperature in September: 67.6°F

The warmest month (with the highest average high temperature) is August (72.1°F).
The month with the lowest average high temperature is February (39.7°F).

  • Average low temperature in September: 63.9°F

The month with the highest average low temperature is August (68.7°F).
The coldest month (with the lowest average low temperature) is February (32.5°F).

[Resources]

Average pressure in September
Nantucket, MA

Average pressure in September - Nantucket, MA
  • Average pressure in September: 30.05"Hg

The month with the highest atmospheric pressure is November (30.06"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

[Resources]

Average wind speed in September
Nantucket, MA

Average wind speed in September - Nantucket, MA
  • Average wind speed in September: 14mph

The windiest month (with the highest average wind speed) is January (18.5mph).
The calmest month (with the lowest average wind speed) is August (11.8mph).

[Resources]

Average humidity in September
Nantucket, MA

Average humidity in September - Nantucket, MA
  • Average humidity in September: 80%

The month with the highest relative humidity is July (86%).
The months with the lowest relative humidity are January, November and December (75%).

[Resources]

Average rainfall in September
Nantucket, MA

Average rainfall in September - Nantucket, MA
  • Average rainfall in September: 2.2"

The wettest month (with the highest rainfall) is October (3.27").
The driest month (with the least rainfall) is November (1.77").

[Resources]

Average rainfall days in September
Nantucket, MA

Average rainfall days in September - Nantucket, MA
  • Average rainfall days in September: 11.7 days

The month with the highest number of rainy days is May (14.3 days).
The month with the least rainy days is February (9.2 days).

[Resources]

Average snowfall in September
Nantucket, MA

Average snowfall in September - Nantucket, MA
  • Average snowfall in September: 0"

The month with the highest snowfall is January (1.06").
The months with the least snowfall are April, May, June, July, August, September and October (0").

[Resources]

Average snowfall days in September
Nantucket, MA

Average snowfall days in September - Nantucket, MA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (5.8 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

[Resources]

Average sea temperature in September
Nantucket, MA

Average sea temperature in September - Nantucket, MA
  • Average sea temperature in September: 65.1°F

The best month for swimming (with the highest average sea temperature) is August (67.6°F).
The coldest month (with the lowest average sea temperature) is February (37.9°F).

[Resources]

Average daylight in September /
Average sunshine in September
Nantucket, MA

Average daylight in September / Average sunshine in September - Nantucket, MA
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in September: 8h and 4min

The months with the most sunshine are July and August (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 4h and 18min).

[Resources]

Average sunshine days in September
Nantucket, MA

Average sunshine days in September - Nantucket, MA
  • Average sunshine days in September: 15.7 days

The month with the most sunshine days is August (16.5 days).
The month with the least sunshine days is January (11.3 days).

[Resources]

Average UV index in September
Nantucket, MA

Average UV index in September - Nantucket, MA
  • Average UV index in September: 5

The months with the highest UV index are July and August (UV index 6).
The months with the lowest UV index are January, February, March and December (UV index 2).

[Resources]

Average cloud cover in September
Nantucket, MA

Average cloud cover in September - Nantucket, MA
  • Average cloud cover in September: 32

The month with the most cloud cover is December (Cloud cover 54).
The month with the least cloud cover is August (Cloud cover 27).

[Resources]

Average visibility in September
Nantucket, MA

Average visibility in September - Nantucket, MA
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

[Resources]

Nantucket, Massachusetts, USA

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location