Measurements:
°C
°F
Nantucket
56°F
W 19 mph
Feels like: 52°F
Precip: 100%
World Resorts USA Nantucket Weather

Nantucket Sea Water Temperature

Current Sea Water Temperature:
+53.6°F
Maximum Sea Water Temperature in May: 62.2°F
Minimum Sea Water Temperature in May: 44.4°F
Average water temperature in May: 53.0°F

Sea Water Temperature for the Last 10 Days:

May 14 53.6°F May 09 51.8°F
May 13 53.4°F May 08 52.0°F
May 12 51.2°F May 07 48.0°F
May 11 52.4°F May 06 50.0°F
May 10 50.0°F May 05 50.8°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: 2025 2024 2023

The average sea surface temperature in August 2025 for Nantucket was 71.9°F. The maximum and minimum values were 69.6°F and 75.8°F respectively.

Sea Water Temperature in July

Select Year: 2025 2024 2023

The average sea surface temperature in July 2025 for Nantucket was 70.7°F. The maximum and minimum values were 65.4°F and 75.4°F respectively.

Sea Water Temperature in September

Select Year: 2025 2024 2023

The average sea surface temperature in September 2025 for Nantucket was 69.7°F. The maximum and minimum values were 68.2°F and 71.6°F respectively.

Best Time to Visit Nantucket
The most sunny months:
June 13 days
October 13 days
September 13 days
The most warm months:
August 73.3 °F
July 72.9 °F
September 69.0 °F
Warmest sea temperature:
August 74.4 °F
July 72.4 °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 +56
Hawaii +76
Honolulu +76
Houston +94
Las Vegas +88
Los Angeles +66
Maui +70
Miami +94
Miami Beach +90
New York +68
San Diego +66
San Francisco +62
Sarasota +94
Tampa +94
24 Hours Weather Forecast
Nantucket
Local time: 13:07
14 may, thursday
1500 56°F
NW
19 mph
1800 56°F
NW
12 mph
2100 54°F
S
6 mph
15 may, friday
0000 54°F
E
7 mph
0300 54°F
E
11 mph
0600 54°F
E
6 mph
0900 54°F
S
4 mph
1200 54°F
W
6 mph