Measurements:
°C
°F
Charlestown
40°F
W 9 mph
Feels like: 34°F
Precip: 78%
World Resorts USA Charlestown Weather

Charlestown Sea Water Temperature

Current Sea Water Temperature:
+39.8°F
Maximum Sea Water Temperature in April: 49.8°F
Minimum Sea Water Temperature in April: 38.2°F
Average water temperature in April: 44.5°F

Sea Water Temperature for the Last 10 Days:

April 03 39.8°F March 29 37.8°F
April 02 40.2°F March 28 38.0°F
April 01 38.2°F March 27 38.6°F
March 31 37.8°F March 26 37.2°F
March 30 38.2°F March 25 37.2°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 35.0 °F
February 35.5 °F
December 41.0 °F
The most rainy months:
October 4 days
November 3 days
April 3 days
The most windy months:
January 13 mph
December 13 mph
March 12 mph

Charlestown on the Weather Map

USA Resorts:
NAME
Chicago +46
Hawaii +74
Honolulu +74
Houston +74
Las Vegas +54
Los Angeles +56
Maui +66
Miami +74
Miami Beach +78
New York +40
San Diego +58
San Francisco +50
Sarasota +72
Tampa +72
Washington +48
24 Hours Weather Forecast
Charlestown
Local time: 05:49
03 apr, friday
0600 40°F
W
9 mph
0900 40°F
NW
6 mph
1200 42°F
NE
8 mph
1500 42°F
NE
12 mph
1800 44°F
NE
14 mph
2100 44°F
NE
14 mph
04 apr, saturday
0000 44°F
NE
17 mph
0300 42°F
NE
13 mph