Measurements:
°C
°F
Nantucket
34°F
SW 15 mph
Feels like: 26°F
Precip: 100%
World Resorts USA Nantucket Weather

Nantucket Sea Water Temperature

Current Sea Water Temperature:
+31.6°F
Maximum Sea Water Temperature in February: 41.4°F
Minimum Sea Water Temperature in February: 29.8°F
Average water temperature in February: 36.2°F

Sea Water Temperature for the Last 10 Days:

February 21 31.6°F February 16 30.6°F
February 20 31.2°F February 15 31.2°F
February 19 31.6°F February 14 30.6°F
February 18 31.2°F February 13 30.6°F
February 17 31.6°F February 12 31.0°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
September 13 days
June 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:
January 34.9 °F
February 35.0 °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 +28
Hawaii +70
Honolulu +70
Houston +74
Las Vegas +42
Los Angeles +48
Maui +66
Miami +86
Miami Beach +78
New York +42
San Diego +50
San Francisco +46
Sarasota +74
Tampa +78
Washington +48
24 Hours Weather Forecast
Nantucket
Local time: 11:00
21 feb, saturday
1200 34°F
SW
15 mph
1500 34°F
S
12 mph
1800 30°F
S
15 mph
2100 28°F
SW
14 mph
22 feb, sunday
0000 30°F
SW
11 mph
0300 30°F
SW
12 mph
0600 30°F
SW
14 mph
0900 30°F
SW
17 mph