World Resorts USA Nantucket Weather

Nantucket sea water temperature

Current sea water temperature:
+47.1°F
Minimum sea water temperature in December: 50.7°F
Maximum sea water temperature in December: 38.8°F
Average sea water temperature in December: 45.1°F

Sea water temperature for the last 10 days:

December 4 47.1°F November 29 47.1°F
December 3 46.9°F November 28 47.1°F
December 2 46.9°F November 27 47.7°F
December 1 48.2°F November 26 47.3°F
November 30 47.1°F November 25 47.5°F

When is the warmest sea in Nantucket?

Based on the data about daily sea water temperature for the last three years the warmest sea in Nantucket was noticed in August, July and September.

Monthly Sea Temperatures in Nantucket, °F

Sea water temperature in August, °F

Show year:
2025
2024
2023

The average sea water temperature in August of 2025 was 69.7°F. The highest and lowest sea temperatures during the month were 73.2°F and 67.6°F.

Sea water temperature in July, °F

Show year:
2025
2024
2023

The average sea water temperature in July of 2025 was 68.7°F. The highest and lowest sea temperatures during the month were 72.9°F and 63.9°F.

Sea water temperature in September, °F

Show year:
2025
2024
2023

The average sea water temperature in September of 2025 was 67.7°F. The highest and lowest sea temperatures during the month were 69.4°F and 66.4°F.

Best time for vacation in Nantucket

Sunniest months:
June 13 days
September 13 days
October 13 days
Warmest months:
August 70.9 °F
July 70.6 °F
September 67.1 °F
Warmest sea temp:
August 72.0 °F
July 70.1 °F
September 68.5 °F
Coldest months:
February 36.5 °F
January 36.9 °F
March 40.4 °F
Rainiest months:
January 4 days
October 4 days
December 3 days
Windiest months:
March 19.1 mph
January 19.0 mph
November 18.6 mph

Nantucket on a weather map

Nantucket
+25°F
SE 32 mph
Feels like: +10°F
Precip.: 0%
Places in USA:
Name
°F
+30°F
+77°F
+77°F
+45°F
+55°F
+70°F
+77°F
+70°F
+25°F
+57°F
+48°F
+63°F
+63°F
+46°F
+5°F
24 Hours Forecast
Nantucket
Local time: 23:45
December 05, friday
0000
25°F
SE
32 mph
0300
21°F
SE
22 mph
0600
21°F
S
16 mph
0900
25°F
S
6 mph
1200
28°F
NE
4 mph
1500
30°F
NE
9 mph
1800
32°F
NE
8 mph
2100
34°F
N
7 mph
Units of measurement: °C / °F