Measurements:
°C
°F
CURRENT WEATHER
09:41
Charlestown
62°F
SW 14 mph
Feels like: 62°F
Precip: 5%
World Resorts USA Charlestown Weather

7 Day Weather Forecast

09.15
tue
DAY
66°F
W 9 mph
precip
3%
NIGHT
64°F
NW 7 mph
precip
10%
09.16
wed
DAY
68°F
NE 9 mph
precip
12%
NIGHT
68°F
NE 11 mph
precip
9%
09.17
thu
DAY
74°F
NE 12 mph
precip
8%
NIGHT
72°F
NE 14 mph
precip
21%
09.18
fri
DAY
74°F
W 11 mph
precip
6%
NIGHT
66°F
SW 9 mph
precip
22%
09.19
sat
DAY
66°F
W 11 mph
precip
3%
NIGHT
72°F
N 20 mph
precip
22%
09.20
sun
DAY
74°F
E 14 mph
precip
41%
NIGHT
66°F
SW 10 mph
precip
17%
09.21
mon
DAY
68°F
W 8 mph
precip
22%
NIGHT
62°F
W 15 mph
precip
37%

Charlestown Sea Water Temperature in September, °F

Select Year: 2026 2025 2024

The average sea surface temperature in September 2026 for Charlestown was 20.7°F. The maximum and minimum values were 20.4°F and 21.3°F respectively.

Charlestown on the Weather Map

Best Time to Visit Charlestown
The most sunny months:
November 17 days
September 14 days
October 14 days
The most warm months:
July 78.9 °F
August 77.8 °F
September 72.1 °F
Warmest sea temperature:
August 73.1 °F
July 71.6 °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
more details