The highest day temperature in September 2026 was 99°F. The lowest night temperature was 61°F. The average values for day and night temperatures during September were 89.0°F и 77.4°F respectivly.

The average sea surface temperature in September 2026 for Charleston was 86.2°F. The maximum and minimum values were 79.0°F and 89.4°F respectively.

You can expect various weather conditions during September. Be ready for sunny, cloudy or even gloomy days.

Precipitation total in September for Charleston is 4.1 in. It makes september one of the most rainy months of the year.

The average wind speed in September is 8.3 mph. This value is relatively stable throughout the year.

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 Charleston in September is 7.2 hours.