The weather in Charleston in September is very hot. The average temperatures are between 23°C and 29°C, drinking water regularly is advisable.
You can expect rain for roughly half of the month of September in Charleston. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
Our weather forecast can give you a great sense of what weather to expect in Charleston in September 2025.
If you’re planning to visit Charleston in the near future, we highly recommend that you review the 14 day weather forecast for Charleston before you arrive.
Temperatures
29° / 23°
Rainy Days
8
Snowy Days
0
Dry Days
22
Rainfall
229
mm
Sun Hours
10.7
Hrs