Measurements:
°C
°F
Charlestown
44°F
SE 7 mph
Feels like: 36°F
Precip: 0%
World Resorts USA Charlestown Weather

Charlestown Sea Water Temperature

Current Sea Water Temperature:
+40.6°F
Maximum Sea Water Temperature in January: 47.2°F
Minimum Sea Water Temperature in January: 38.2°F
Average water temperature in January: 42.6°F

Sea Water Temperature for the Last 10 Days:

January 08 40.6°F January 03 40.4°F
January 07 39.8°F January 02 41.4°F
January 06 39.8°F January 01 41.8°F
January 05 40.2°F December 31 41.8°F
January 04 40.0°F December 30 42.2°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 35.7 °F
February 36.2 °F
December 41.0 °F
The most rainy months:
October 4 days
November 3 days
January 3 days
The most windy months:
December 13 mph
March 12 mph
January 12 mph

Charlestown on the Weather Map

USA Resorts:
NAME
Chicago +54
Hawaii +78
Honolulu +78
Houston +78
Las Vegas +54
Los Angeles +58
Maui +72
Miami +86
Miami Beach +80
New York +52
San Diego +64
San Francisco +52
Sarasota +82
Tampa +88
Washington +60
24 Hours Weather Forecast
Charlestown
Local time: 15:32
08 jan, thursday
1800 42°F
SE
5 mph
2100 38°F
SE
5 mph
09 jan, friday
0000 36°F
E
3 mph
0300 36°F
E
3 mph
0600 36°F
N
4 mph
0900 38°F
N
7 mph
1200 40°F
N
12 mph
1500 40°F
N
14 mph