World Resorts USA Nantucket Weather

Nantucket sea water temperature

Current sea water temperature:
+39.9°F
Minimum sea water temperature in March: 44.6°F
Maximum sea water temperature in March: 36.1°F
Average sea water temperature in March: 40.4°F

Sea water temperature for the last 10 days:

March 16 39.9°F March 11 40.3°F
March 15 41.4°F March 10 40.1°F
March 14 40.3°F March 9 37.4°F
March 13 39.9°F March 8 38.1°F
March 12 40.8°F March 7 37.0°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:
October 13 days
June 13 days
September 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 36.1 °F
January 36.4 °F
March 40.4 °F
Rainiest months:
October 4 days
January 3 days
December 3 days
Windiest months:
March 19.1 mph
January 19.0 mph
December 18.9 mph

Nantucket on a weather map

Nantucket
+55°F
N 41 mph
Feels like: +46°F
Precip.: 100%
Places in USA:
Name
°F
+37°F
+75°F
+75°F
+68°F
+66°F
+73°F
+75°F
+70°F
+52°F
+66°F
+68°F
+61°F
+59°F
+39°F
+19°F
24 Hours Forecast
Nantucket
Local time: 00:27
March 17, tuesday
0300
55°F
N
43 mph
0600
45°F
NE
29 mph
0900
39°F
E
37 mph
1200
39°F
E
34 mph
1500
39°F
E
30 mph
1800
37°F
E
28 mph
2100
37°F
E
25 mph
March 18, wednesday
0000
34°F
SE
24 mph
Units of measurement: °C / °F