Charleston weather in September: Charleston, South Carolina: normal highs, lows, rain and records for September
Charleston in September has a normal high of 85°F and a normal low of 68°F, a daily mean of 77°F, falling from 88°F on the 1st to 82°F by the 30th. Measurable precipitation falls on 10 days in a normal September, 6.01 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 30°C and low of 20°C, 153 mm of precipitation in September.
- NOAA stationCharleston International Airport
- Station IDUSW00013880
- Location32.90°N 80.04°W
- Elevation40 ft (12 m)
- From the center6 miles
- Population157,665
- Jan 60° 39°
- Feb 64° 42°
- Mar 70° 47°
- Apr 77° 55°
- May 84° 63°
- Jun 89° 70°
- Jul 91° 74°
- Aug 90° 73°
- Sep 85° 68°
- Oct 78° 58°
- Nov 69° 47°
- Dec 63° 42°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Charleston in September?
The normal high is 85°F and the normal low 68°F, for a daily mean of 76.9°F. September is 4.5°F cooler than August and 9.1°F warmer than October. September is the 4th warmest month of the year in Charleston and the 4th wettest. Across the month the normal high falls 6°F, from 88°F on September 1 to 82°F on September 30. From one year to the next September's mean temperature typically moves about 1.7°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 75°F and 79°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 38%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 88°F | 72°F | 38% | 26% |
| September 8 | 87°F | 70°F | 36% | 24% |
| September 15 | 86°F | 69°F | 34% | 22% |
| September 22 | 84°F | 67°F | 32% | 21% |
| September 30 | 82°F | 64°F | 29% | 19% |
Every day of September: normal high, low and chance of precipitation (warmest afternoon September 1, coldest night September 30)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| September 1 | 88°F | 72°F | 38% | 26% | 12 h 50 min |
| September 2 | 88°F | 71°F | 38% | 26% | 12 h 50 min |
| September 3 | 88°F | 71°F | 37% | 25% | 12 h 50 min |
| September 4 | 88°F | 71°F | 37% | 25% | 12 h 50 min |
| September 5 | 87°F | 71°F | 37% | 25% | 12 h 50 min |
| September 6 | 87°F | 71°F | 36% | 25% | 12 h 40 min |
| September 7 | 87°F | 71°F | 36% | 24% | 12 h 40 min |
| September 8 | 87°F | 70°F | 36% | 24% | 12 h 40 min |
| September 9 | 87°F | 70°F | 35% | 24% | 12 h 40 min |
| September 10 | 87°F | 70°F | 35% | 23% | 12 h 40 min |
| September 11 | 86°F | 70°F | 35% | 23% | 12 h 30 min |
| September 12 | 86°F | 69°F | 34% | 23% | 12 h 30 min |
| September 13 | 86°F | 69°F | 34% | 23% | 12 h 30 min |
| September 14 | 86°F | 69°F | 34% | 23% | 12 h 30 min |
| September 15 | 86°F | 69°F | 34% | 22% | 12 h 30 min |
| September 16 | 86°F | 69°F | 33% | 22% | 12 h 20 min |
| September 17 | 85°F | 68°F | 33% | 22% | 12 h 20 min |
| September 18 | 85°F | 68°F | 33% | 22% | 12 h 20 min |
| September 19 | 85°F | 68°F | 33% | 22% | 12 h 20 min |
| September 20 | 85°F | 67°F | 32% | 21% | 12 h 20 min |
| September 21 | 84°F | 67°F | 32% | 21% | 12 h 10 min |
| September 22 | 84°F | 67°F | 32% | 21% | 12 h 10 min |
| September 23 | 84°F | 67°F | 32% | 21% | 12 h 10 min |
| September 24 | 84°F | 66°F | 31% | 21% | 12 h 10 min |
| September 25 | 84°F | 66°F | 31% | 21% | 12 h 10 min |
| September 26 | 83°F | 66°F | 31% | 20% | 12 h |
| September 27 | 83°F | 65°F | 31% | 20% | 12 h |
| September 28 | 83°F | 65°F | 30% | 20% | 12 h |
| September 29 | 83°F | 65°F | 30% | 19% | 12 h |
| September 30 | 82°F | 64°F | 29% | 19% | 12 h |
- Normal high
- 85°FSeptember average
- Normal low
- 68°FSeptember average
- Precipitation
- 6.01 inmonth total
- Days with precipitation
- 100.01 inch or more
- Days at 90°F or more
- 6
- Daylight
- 12 h 50 min to 12 hSeptember 1 to September 30
- Days at 70°F or more
- 30
- Days at 80°F or more
- 26
- Sunshine
- 80%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00013880; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Charleston in September?
On a given September day the chance of 0.01 inch or more is 34% on average, highest around September 1 (38%). In all, 6.01 in falls on 10 days of a normal September, 2 of them with an inch or more.
In a normal September in Charleston, 6 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00013880.
How humid and windy is Charleston in September?
At 3 p.m. the normal temperature is 80°F with 58% relative humidity and a dew point of 64°F; at 6 a.m. it is 66°F with 90% humidity. The wind averages 7.2 mph, most often from the east-northeast in the afternoon.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 66°F | 63°F | 90% | 5.9 mph | 54% |
| 9 a.m. | 73°F | 65°F | 76% | 8.3 mph | 49% |
| noon | 79°F | 64°F | 61% | 9.0 mph | 38% |
| 3 p.m. | 80°F | 64°F | 58% | 9.7 mph | 35% |
| 6 p.m. | 75°F | 65°F | 71% | 8.0 mph | 52% |
| 9 p.m. | 71°F | 65°F | 83% | 5.9 mph | 63% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00013880. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for September in Charleston?
The warmest September temperature on Charleston's official record (since 1937) is 99°F, on September 5, 1944; the coldest is 42°F, on September 30, 1967. The wettest September brought 17.31 in (1945).
The September mean against the 1991-2020 normal of 76.9°F: 2021 76.2°F (−0.8), 2022 76.5°F (−0.4), 2023 77.2°F (+0.3), 2024 77.2°F (+0.3), 2025 75.9°F (−1.0), 2026 78.5°F (+1.6). 3 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 76.2°F | −0.8°F | 7.28 in |
| 2022 | 76.5°F | −0.4°F | 7.92 in |
| 2023 | 77.2°F | +0.3°F | 7.97 in |
| 2024 | 77.2°F | +0.3°F | 3.53 in |
| 2025 | 75.9°F | −1.0°F | 0.98 in |
| 2026 | 78.5°F | +1.6°F | 3.54 in |
Source: records: ACIS, NWS threaded record CHSthr; recent months: ACIS, station USW00013880. Records and recent months use complete months only.
How does September in Charleston compare across South Carolina?
Across the 73 places PlainClimate covers in South Carolina, September normal highs run from 71°F in Caesars Head to 87°F in Barnwell; Charleston's is 85°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.
Other months and places
- Charleston in August90°F by day, 73°F at night
- Charleston in October78°F by day, 58°F at night
- Charleston through the yearEvery month, frost dates, records and recent years
- South Carolina in SeptemberThe statewide normal and the warmest and coolest places
- Barnwell: South Carolina's warmest Septembernormal high 87°F