Climate averages 1991–2020
Charleston weather
in September.
A warm, wet month: the 4th warmest and the 9th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in Charleston: daytime highs average 27.6°C and nights cool to about 22.2°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 128 mm of rain on roughly 13 days, which makes September a wet month (the 9th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 24 min on an average September day.
The nearest other city in this atlas is North Charleston (10 km away). In September its highs average 27.9°C, about as warm as Charleston, with 128 mm of rain.
Among the 498 cities listed in the United States, Charleston ranks joint 216th of 498 for the warmest September highs and joint 457th of 498 for the driest September (rainfall, lowest first). The mean September high of those 498 cities is 26.9°C; Charleston is 0.7°C warmer than that mean.
From September to October, average highs fall by 3.8°C to 23.8°C, and monthly rainfall falls from 128 mm to 101 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Charleston climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 14.4°C7.1°C | 7.1°C | 81 | 8.4 | 10.310 h |
| February | 15.9°C8.4°C | 8.4°C | 84 | 7.8 | 11.011 h |
| March | 18.6°C11.2°C | 11.2°C | 81 | 8.2 | 12.012 h |
| April | 22.3°C15.0°C | 15.0°C | 74 | 7.5 | 13.013 h |
| May | 26.2°C19.5°C | 19.5°C | 68 | 9.0 | 13.814 h |
| June | 29.0°C23.2°C | 23.2°C | 130 | 16.3 | 14.314 h |
| July | 30.4°C24.9°C | 24.9°C | 138 | 17.7 | 14.114 h |
| August | 29.6°C24.5°C | 24.5°C | 160 | 18.9 | 13.413 h |
| September, selected | 27.6°C22.2°C | 22.2°C | 128 | 13.2 | 12.412 h |
| October | 23.8°C17.3°C | 17.3°C | 101 | 7.8 | 11.411 h |
| November | 19.1°C12.1°C | 12.1°C | 65 | 6.7 | 10.511 h |
| December | 15.9°C8.9°C | 8.9°C | 86 | 7.6 | 10.010 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- North Charleston in SeptemberUnited States · 10 kmHigh 27.9°C · Low 21.3°C · 128 mm rain
- Savannah in SeptemberUnited States · 134 kmHigh 28.4°C · Low 21.8°C · 122 mm rain
- Columbia (South Carolina), United States in SeptemberUnited States · 170 kmHigh 28.3°C · Low 19.0°C · 94 mm rain
- Wilmington (North Carolina), United States in SeptemberUnited States · 245 kmHigh 26.8°C · Low 21.1°C · 166 mm rain
- Rock Hill in SeptemberUnited States · 259 kmHigh 27.4°C · Low 18.4°C · 93 mm rain
- Fayetteville in SeptemberUnited States · 271 kmHigh 27.6°C · Low 19.0°C · 128 mm rain
- Charlotte in SeptemberUnited States · 285 kmHigh 27.1°C · Low 17.7°C · 98 mm rain
- Concord (North Carolina), United States in SeptemberUnited States · 299 kmHigh 27.2°C · Low 18.1°C · 103 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Charleston) is explained once on the Charleston year overview and on the Sources, method and limits page.
North Charleston lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.