Measurements:
°C
°F
Block Island
82°F
NE 14 mph
Feels like: 86°F
Precip: 5%
World Resorts USA Block Island Weather

Block Island Sea Water Temperature

Current Sea Water Temperature:
+72.8°F
Maximum Sea Water Temperature in August: 76.8°F
Minimum Sea Water Temperature in August: 68.8°F
Average water temperature in August: 72.4°F

Sea Water Temperature for the Last 10 Days:

August 25 72.8°F August 20 72.6°F
August 24 71.2°F August 19 72.2°F
August 23 71.6°F August 18 72.2°F
August 22 71.8°F August 17 72.0°F
August 21 72.8°F August 16 73.0°F

When is the Warmest Sea for Block Island?

According to our data for the last three years for Block Island 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 Block Island was 72.5°F. The maximum and minimum values were 70.6°F and 74.8°F respectively.

Sea Water Temperature in July

Select Year: 2026 2025 2024

The average sea surface temperature in July 2026 for Block Island was 69.2°F. The maximum and minimum values were 67.2°F and 71.4°F respectively.

Sea Water Temperature in September

Select Year: 2025 2024 2023

The average sea surface temperature in September 2025 for Block Island was 70.0°F. The maximum and minimum values were 68.4°F and 71.0°F respectively.

Best Time to Visit Block Island
The most sunny months:
November 16 days
December 14 days
June 14 days
The most warm months:
July 77.6 °F
August 76.1 °F
September 70.9 °F
Warmest sea temperature:
August 72.3 °F
July 70.5 °F
September 70.3 °F
The most cold months:
January 35.4 °F
February 35.4 °F
December 41.7 °F
The most rainy months:
October 4 days
January 3 days
March 3 days
The most windy months:
December 16 mph
January 16 mph
November 16 mph

Block Island on the Weather Map

USA Resorts:
NAME
Boston +80
Chicago +80
Hawaii +84
Houston +106
Las Vegas +116
Los Angeles +96
Maui +70
Miami +92
Myrtle Beach +84
New York +82
San Diego +96
San Francisco +64
Santa Monica +86
Sarasota +92
Washington +84
24 Hours Weather Forecast
Block Island
Local time: 17:36
25 aug, tuesday
1800 82°F
NE
14 mph
2100 72°F
E
9 mph
26 aug, wednesday
0000 70°F
SE
10 mph
0300 66°F
SE
12 mph
0600 66°F
SE
9 mph
0900 66°F
SE
8 mph
1200 72°F
NE
11 mph
1500 72°F
NE
18 mph