Measurements:
°C
°F
Nantucket
36°F
NE 17 mph
Feels like: 28°F
Precip: 0%
World Resorts USA Nantucket Weather

Nantucket Sea Water Temperature

Current Sea Water Temperature:
+38.8°F
Maximum Sea Water Temperature in March: 44.0°F
Minimum Sea Water Temperature in March: 34.6°F
Average water temperature in March: 39.3°F

Sea Water Temperature for the Last 10 Days:

March 13 38.8°F March 08 36.8°F
March 12 39.8°F March 07 35.6°F
March 11 39.2°F March 06 35.6°F
March 10 39.0°F March 05 35.6°F
March 09 36.0°F March 04 34.6°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:
October 13 days
June 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 39.3 °F
The most rainy months:
October 4 days
January 3 days
December 3 days
The most windy months:
March 19 mph
January 19 mph
December 19 mph

Nantucket on the Weather Map

USA Resorts:
NAME
Chicago +42
Hawaii +76
Honolulu +76
Houston +82
Las Vegas +96
Los Angeles +100
Maui +70
Miami +84
Miami Beach +82
New York +42
San Diego +94
San Francisco +72
Sarasota +80
Tampa +80
Washington +56
24 Hours Weather Forecast
Nantucket
Local time: 17:03
13 mar, friday
1800 36°F
NE
17 mph
2100 36°F
N
22 mph
14 mar, saturday
0000 38°F
N
29 mph
0300 42°F
NE
37 mph
0600 42°F
NE
27 mph
0900 40°F
E
26 mph
1200 42°F
E
39 mph
1500 42°F
E
40 mph