Measurements:
°C
°F
Nantucket
42°F
SE 7 mph
Feels like: 38°F
Precip: 0%
World Resorts USA Nantucket Weather

Nantucket Sea Water Temperature

Current Sea Water Temperature:
+33.8°F
Maximum Sea Water Temperature in January: 44.8°F
Minimum Sea Water Temperature in January: 32.0°F
Average water temperature in January: 39.3°F

Sea Water Temperature for the Last 10 Days:

January 08 33.8°F January 03 36.8°F
January 07 36.8°F January 02 35.8°F
January 06 36.6°F January 01 37.6°F
January 05 35.8°F December 31 37.2°F
January 04 36.0°F December 30 38.4°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: 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
September 13 days
October 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 35.0 °F
January 35.5 °F
March 39.3 °F
The most rainy months:
January 4 days
October 4 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 +54
Hawaii +78
Honolulu +78
Houston +78
Las Vegas +54
Los Angeles +58
Maui +72
Miami +86
Miami Beach +80
New York +52
San Diego +64
San Francisco +52
Sarasota +82
Tampa +88
Washington +60
24 Hours Weather Forecast
Nantucket
Local time: 15:30
08 jan, thursday
1800 36°F
S
4 mph
2100 36°F
E
4 mph
09 jan, friday
0000 36°F
NE
7 mph
0300 36°F
NE
6 mph
0600 36°F
N
8 mph
0900 36°F
N
11 mph
1200 38°F
N
16 mph
1500 38°F
N
16 mph