Measurements:
°C
°F
Charlestown
64°F
NE 12 mph
Feels like: 64°F
Precip: 4%
World Resorts USA Charlestown Weather

Charlestown Sea Water Temperature

Current Sea Water Temperature:
+56.6°F
Maximum Sea Water Temperature in June: 69.4°F
Minimum Sea Water Temperature in June: 55.2°F
Average water temperature in June: 62.6°F

Sea Water Temperature for the Last 10 Days:

June 04 56.6°F May 29 57.0°F
June 03 55.2°F May 28 56.0°F
June 01 55.4°F May 27 54.8°F
May 31 55.6°F May 26 55.4°F
May 30 57.2°F May 25 56.4°F

When is the Warmest Sea for Charlestown?

According to our data for the last three years for Charlestown 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 Charlestown was 71.8°F. The maximum and minimum values were 69.8°F and 74.4°F respectively.

Sea Water Temperature in July

Select Year: 2025 2024 2023

The average sea surface temperature in July 2025 for Charlestown was 71.3°F. The maximum and minimum values were 67.4°F and 74.2°F respectively.

Sea Water Temperature in September

Select Year: 2025 2024 2023

The average sea surface temperature in September 2025 for Charlestown was 70.1°F. The maximum and minimum values were 68.6°F and 71.8°F respectively.

Best Time to Visit Charlestown
The most sunny months:
November 17 days
October 14 days
September 14 days
The most warm months:
July 79.6 °F
August 78.4 °F
September 72.1 °F
Warmest sea temperature:
August 73.1 °F
July 71.7 °F
September 70.6 °F
The most cold months:
January 35.0 °F
February 35.5 °F
December 41.0 °F
The most rainy months:
October 4 days
November 3 days
January 2 days
The most windy months:
January 13 mph
December 13 mph
March 12 mph

Charlestown on the Weather Map

USA Resorts:
NAME
Boston +90
Chicago +76
Hawaii +78
Honolulu +78
Houston +86
Las Vegas +92
Los Angeles +70
Maui +70
Miami +82
Miami Beach +84
New York +94
San Diego +64
San Francisco +60
Sarasota +94
Tampa +92
24 Hours Weather Forecast
Charlestown
Local time: 12:54
04 jun, thursday
1500 66°F
N
16 mph
1800 66°F
NE
14 mph
2100 62°F
NE
11 mph
05 jun, friday
0000 60°F
NE
10 mph
0300 60°F
NE
11 mph
0600 62°F
E
9 mph
0900 66°F
E
9 mph
1200 70°F
E
12 mph