Charleston, SC weather in September
In September, Charleston sees highs around 83°F and lows around 73°F: warm and oppressively humid, with some rain. Expect about 9 wet days.
- Normal high
- 83°F
- Normal low
- 73°F
- Wet days
- 9
- 5.3 in total
- Muggy days
- 23
- dew point 65°F+
How September changes from start to finish
| September 1 | September 30 | |
|---|---|---|
| Normal high | 85°F | 80°F |
| Normal low | 75°F | 69°F |
| Chance of a wet day | 33% | 27% |
| Sunrise / sunset | 6:54 am / 7:44 pm | 7:13 am / 7:06 pm |
| Daylight | 12.8 h | 11.9 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Eastern Time).
A typical September day
- 6 am70°Fdew point 67°F
- 9 am77°Fdew point 69°F
- Noon82°Fdew point 68°F
- 3 pm83°Fdew point 68°F
- 6 pm78°Fdew point 68°F
- 9 pm74°Fdew point 69°F
NOAA hourly normals (local standard time) from Charleston Intl Airport (11 mi away); average wind 7 mph; clear or few clouds in 34% of daytime hours, mostly cloudy or overcast in 39%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F3 of 30
- Beach dayshigh 80-95°F, under 0.05 in of rain, afternoon wind under 15 mph18 of 30
- Hot dayshigh 90°F or more2 of 30
- Muggy daysdaily mean dew point 65°F or more23 of 30
- Wet daysat least 0.01 in of rain or melted snow9 of 30
- Notable rainat least 0.10 in6 of 30
- Freezing nightslow 32°F or below0 of 30
Average days per September, counted from daily records for each year 1991-2020.
Rain in September
Normal precipitation is 5.3 in; a dry September brings about 4.0 in and a wet one about 6.5 in (25th and 75th percentiles). About 3 days bring half an inch or more, and about 1 an inch or more.
How September varies from year to year
- Warmest September, 1991-20201998: average high 87°F
- Coolest September1995: average high 80°F
- Wettest September1998: 10.8 in
- Driest September2012: 0.6 in
- Highest reading96°F (September 4, 2020)
- Lowest reading55°F (September 23, 1999)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
September compared with August and October
| August | September | October | |
|---|---|---|---|
| Normal high | 86°F | 83°F | 76°F |
| Normal low | 77°F | 73°F | 63°F |
| Wet days | 12 | 9 | 7 |
| Comfortable days | 0 | 3 | 13 |
| Daylight | 13.3 h | 12.4 h | 11.4 h |
Highs change by -3°F from August and -7°F into October.
Nearby alternatives in September
- Warmer: Columbia, SC106 mi · high 89°F · 8 wet days
How Charleston ranks in September
- Normal high171st warmest of 378 cities; 4th of 5 in South Carolina
- Wet days224th driest of 378
- Comfortable days238th most of 342
What to pack for Charleston in September
- A rain jacket or umbrella – rain on about 9 days
- A swimsuit – about 18 beach days
Heating and cooling
September has 1 heating degree days and 377 cooling degree days (base 65°F), 9% of the year's total heating and cooling demand.
Questions
How hot is Charleston in September?
The normal high is 83°F and the normal low is 73°F. From 1991 to 2020 the hottest September reading was 96°F (September 4, 2020).
Does it rain a lot in Charleston in September?
About 9 days in September have at least 0.01 in of precipitation, and the normal total is 5.3 in. The wettest September in 1991-2020 was in 1998 (10.8 in); the driest was in 2012 (0.6 in).
Is September a good time to visit Charleston?
September ranks 10th of 12 months on our comfort score for Charleston (51 out of 100). It has about 3 comfortable days and about 2 days at 90°F or hotter. The best month is April.
Where the numbers come from
- Temperature, rain and frost dates: Charleston City (USW00013782), 0.2 mi NNW of the city center, 10 ft . NOAA normals and daily records, 1991-2020.
- Snowfall, snow depth, humidity and wind by hour and cloud cover: Charleston Intl Airport (USW00013880), 11 mi NW of the city center, 40 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Charleston AFB/International Airport (722080-13880), 11 mi NW of the city center, 39 ft . Hourly observations, 1991-2020.