Charlestown Weather: September
 |
Average Day Temperature: | 72.1°F |
|
Average Night Temperature: | 64.2°F |
|
Sea Water Temperature: | 70.6°F |
|
Number of Sunny Days: | 14 days |
| Sunshine Hours: | 11.8 - 13.1 hours | |
|
Number of Rainy Days: | 2 days |
| Precipitation Totals: | 1.0 in | |
| detailed information | ||
forecast
| Charlestown |
Temperature
| Charlestown |
Air Temperature in September, °F
The highest day temperature in September 2025 was 76°F. The lowest night temperature was 59°F. The average values for day and night temperatures during September were 71.1°F и 65.8°F respectivly.
Charlestown Water Sea Temperature in September, °F
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.
Most of the days in September are sunny but you can also expect cloudy and gloomy days.
Precipitation Totals in September, in
Precipitation total in September for Charlestown is 1.0 in.
The average wind speed in September is 9.8 mph. It makes September one of the most windless months of the year for Charlestown.
We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Charlestown in September is 7.7 hours.
Charlestown on the Weather Map
| Chicago |  |
+42 |
| Hawaii |  |
+76 |
| Honolulu | |
+76 |
| Houston |  |
+82 |
| Las Vegas | |
+96 |
| Los Angeles | |
+100 |
| Maui |  |
+70 |
| Miami |  |
+84 |
| Miami Beach |  |
+82 |
| New York | |
+42 |
| San Diego | |
+94 |
| San Francisco | |
+72 |
| Sarasota | |
+80 |
| Tampa | |
+80 |
| Washington | |
+56 |
| 1800 |  |
42°F | NE 14 mph |
| 2100 |  |
38°F | N 21 mph |
| 0000 |  |
38°F | N 31 mph |
| 0300 | |
40°F | NE 28 mph |
| 0600 | |
38°F | NE 22 mph |
| 0900 | |
38°F | E 29 mph |
| 1200 |  |
40°F | E 31 mph |
| 1500 | |
42°F | E 28 mph |