Measurements:
°C
°F
Nantucket
64°F
SW 16 mph
Feels like: 64°F
Precip: 5%
World Resorts USA Nantucket Weather

Nantucket Sea Water Temperature

Current Sea Water Temperature:
+71.6°F
Maximum Sea Water Temperature in September: 76.8°F
Minimum Sea Water Temperature in September: 61.8°F
Average water temperature in September: 70.7°F

Sea Water Temperature for the Last 10 Days:

September 15 71.6°F September 10 71.6°F
September 14 69.2°F September 09 71.6°F
September 13 71.8°F September 08 73.0°F
September 12 71.6°F September 07 72.4°F
September 11 71.4°F September 06 73.4°F

When is the Warmest Sea for Nantucket?

According to our data for the last three years for Nantucket the highest average sea water temperature was in August, July and September.

Average Water Temperature by Month, °F

Sea Water Temperature in August

Select Year: 2026 2025 2024

The average sea surface temperature in August 2026 for Nantucket was 73.9°F. The maximum and minimum values were 69.6°F and 76.4°F respectively.

Sea Water Temperature in July

Select Year: 2026 2025 2024

The average sea surface temperature in July 2026 for Nantucket was 71.7°F. The maximum and minimum values were 68.6°F and 74.2°F respectively.

Sea Water Temperature in September

Select Year: 2026 2025 2024

The average sea surface temperature in September 2026 for Nantucket was 72.2°F. The maximum and minimum values were 69.2°F and 74.8°F respectively.

Best Time to Visit Nantucket
The most sunny months:
June 14 days
September 13 days
October 13 days
The most warm months:
August 74.1 °F
July 73.9 °F
September 69.0 °F
Warmest sea temperature:
August 74.3 °F
July 72.3 °F
September 70.6 °F
The most cold months:
February 34.6 °F
January 34.9 °F
March 39.7 °F
The most rainy months:
October 4 days
January 3 days
December 3 days
The most windy months:
January 19 mph
March 19 mph
December 19 mph

Nantucket on the Weather Map

USA Resorts:
NAME
Boston +62
Chicago +66
Hawaii +80
Las Vegas +80
Los Angeles +72
Maui +66
Miami +88
Myrtle Beach +78
New York +66
Panama City Beach +90
San Diego +70
San Francisco +60
Santa Monica +72
Sarasota +86
Washington +66
24 Hours Weather Forecast
Nantucket
Local time: 09:41
15 sep, tuesday
1200 64°F
SW
15 mph
1500 64°F
SW
13 mph
1800 64°F
SW
12 mph
2100 62°F
W
11 mph
16 sep, wednesday
0000 62°F
W
7 mph
0300 62°F
NW
3 mph
0600 62°F
N
1 mph
0900 62°F
N
4 mph