The highest day temperature in August 2025 was 103°F. The lowest night temperature was 75°F. The average values for day and night temperatures during August were 89.8°F и 80.2°F respectivly.

The average sea surface temperature in August 2025 for Charleston was 87.9°F. The maximum and minimum values were 85.6°F and 91.0°F respectively.

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

Precipitation total in August for Charleston is 5.3 in. It makes august the most rainy month of the year.

The average wind speed in August is 7.7 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 August is 7.6 hours.