Charleston weather in September
Temperature, sea and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Good
Best time to visit: May – October
What is the weather like in Charleston in September?
In September, Charleston is hot: daytime highs average 28 °C, and even at night it stays warm at around 22 °C. The sea averages 27.1 °C – lovely and warm for swimming. Expect around 6 hours of sunshine a day. Rain is frequent, with about 13 rainy days and 131 mm in total. The air is often humid and muggy. All in all, September is a good month for a holiday in Charleston.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 72 | 77 | 79 |
| Day | 30° | 28° | 24° |
| Night | 25° | 22° | 17° |
| Sea | 29° | 27° | 24° |
| Sun | 7 h | 6 h | 6 h |
| Rain days | 19 | 13 | 7 |
More details for September
- Daylight
- 12 h 25 min07:02 – 19:28
- UV index
- 8 · very highclear sky, noon (estimate)All months
- Muggy days
- 25 daysdew point 18 °C or moreAll months
- Wind
- 18 km/haverage daily peakAll months
- Cloud cover
- 54 %on averageAll months
- Hot days
- 4 days30 °C or moreAll months
- Time zone
- UTC−4America/New_York
How the score comes together
- Temperatureweight 35 %100 %
- Seaweight 25 %100 %
- Sunshineweight 20 %52 %
- Few rainy daysweight 20 %34 %
Each factor is rated from 0 to 100 % and weighted for the travel style “Sun, sea & sand”.
What to pack in September
- Swimwear
- Sunscreen
- Sunglasses & sun hat
- Light, breathable clothes
- Insect repellent
- Rain jacket or umbrella
Charleston in September: quick answers
Is Charleston hot in September?
Yes. In September, Charleston is hot: daytime highs average 28 °C and nights stay around 22 °C. On about 4 days the thermometer climbs to 30 °C or more.
Can you swim in Charleston in September?
Yes. In September the sea averages 27.1 °C – lovely and warm for swimming.
Does it rain much in Charleston in September?
Rain is frequent, with about 13 rainy days and 131 mm in total.
Charleston month by month
The whole year in CharlestonAll destinations: USAWhere to go in SeptemberSea temperature in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences