Measurements:
°C
°F
Nantucket
58°F
SE 14 mph
Feels like: 54°F
Precip: 9%
World Resorts USA Nantucket Weather

Nantucket Sea Water Temperature

Current Sea Water Temperature:
+57.6°F
Maximum Sea Water Temperature in October: 70.6°F
Minimum Sea Water Temperature in October: 56.6°F
Average water temperature in October: 62.8°F

Sea Water Temperature for the Last 10 Days:

October 26 57.6°F October 21 59.8°F
October 25 57.0°F October 20 59.6°F
October 24 57.0°F October 19 60.6°F
October 23 59.4°F October 18 61.8°F
October 22 59.4°F October 17 63.2°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 69.7°F. The maximum and minimum values were 60.0°F and 74.8°F respectively.

Best Time to Visit Nantucket
The most sunny months:
June 14 days
July 12 days
August 12 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 70.5 °F
The most cold months:
February 34.6 °F
January 34.9 °F
March 39.7 °F
The most rainy months:
January 3 days
October 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
F°
Boston +58
Chicago +58
Hawaii +80
Houston +74
Las Vegas +64
Los Angeles +74
Maui +72
Miami +82
New York +62
Panama City Beach +64
San Diego +74
San Francisco +60
Santa Monica +72
Tampa +74
Washington +58
24 Hours Weather Forecast
Nantucket
Local time: 23:52
27 oct, tuesday
0000 58°F
SE
14 mph
0300 56°F
S
17 mph
0600 54°F
SW
20 mph
0900 52°F
SW
21 mph
1200 50°F
SW
19 mph
1500 50°F
SW
14 mph
1800 48°F
SW
11 mph
2100 48°F
W
9 mph