Measurements:
°C
°F
Charlestown
22°F
SE 21 mph
Feels like: 4°F
Precip: 0%
World Resorts USA Charlestown Weather

Charlestown Sea Water Temperature

Current Sea Water Temperature:
+49.8°F
Maximum Sea Water Temperature in December: 54.6°F
Minimum Sea Water Temperature in December: 43.0°F
Average water temperature in December: 49.1°F

Sea Water Temperature for the Last 10 Days:

December 04 49.8°F November 29 51.4°F
December 03 50.6°F November 28 51.8°F
December 02 50.8°F November 27 51.6°F
December 01 51.2°F November 26 51.6°F
November 30 51.2°F November 25 51.6°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
September 14 days
October 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 35.7 °F
February 36.2 °F
December 41.7 °F
The most rainy months:
October 4 days
November 3 days
January 3 days
The most windy months:
March 12 mph
January 12 mph
November 12 mph

Charlestown on the Weather Map

USA Resorts:
NAME
Chicago 0
Hawaii +78
Honolulu +78
Houston +46
Las Vegas +44
Los Angeles +56
Maui +72
Miami +72
Miami Beach +80
New York +20
San Diego +58
San Francisco +48
Sarasota +64
Tampa +64
Washington +28
24 Hours Weather Forecast
Charlestown
Local time: 00:59
05 dec, friday
0300 18°F
S
12 mph
0600 16°F
S
9 mph
0900 20°F
S
4 mph
1200 26°F
N
5 mph
1500 28°F
NE
9 mph
1800 30°F
NE
6 mph
2100 34°F
NE
5 mph
06 dec, saturday
0000 36°F
NE
4 mph