Charleston, SC weather in August
Charleston is warm and oppressively humid in August, with frequent rain: highs average 86°F and nights drop to about 77°F. Rain falls on about 12 days. This is the peak of the warm season in Charleston.
- Normal high
- 86°F
- Normal low
- 77°F
- Wet days
- 12
- 6.1 in total
- Muggy days
- 30
- dew point 65°F+
How August changes from start to finish
| August 1 | August 31 | |
|---|---|---|
| Normal high | 88°F | 85°F |
| Normal low | 77°F | 75°F |
| Chance of a wet day | 39% | 35% |
| Sunrise / sunset | 6:33 am / 8:18 pm | 6:53 am / 7:46 pm |
| Daylight | 13.8 h | 12.9 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 August day
- 6 am74°Fdew point 72°F
- 9 am82°Fdew point 73°F
- Noon87°Fdew point 72°F
- 3 pm87°Fdew point 72°F
- 6 pm83°Fdew point 72°F
- 9 pm78°Fdew point 73°F
NOAA hourly normals (local standard time) from Charleston Intl Airport (11 mi away); average wind 7 mph; clear or few clouds in 31% 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°F0 of 31
- Beach dayshigh 80-95°F, under 0.05 in of rain, afternoon wind under 15 mph20 of 31
- Hot dayshigh 90°F or more7 of 31
- Muggy daysdaily mean dew point 65°F or more30 of 31
- Wet daysat least 0.01 in of rain or melted snow12 of 31
- Notable rainat least 0.10 in8 of 31
- Freezing nightslow 32°F or below0 of 31
Average days per August, counted from daily records for each year 1991-2020.
Rain in August
Normal precipitation is 6.1 in; a dry August brings about 3.4 in and a wet one about 9.0 in (25th and 75th percentiles). About 4 days bring half an inch or more, and about 2 an inch or more.
How August varies from year to year
- Warmest August, 1991-20201999: average high 90°F
- Coolest August2004: average high 83°F
- Wettest August1992: 14.2 in
- Driest August1998: 1.5 in
- Highest reading103°F (August 1, 1999)
- Lowest reading66°F (August 15, 2013)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
August compared with July and September
| July | August | September | |
|---|---|---|---|
| Normal high | 88°F | 86°F | 83°F |
| Normal low | 77°F | 77°F | 73°F |
| Wet days | 12 | 12 | 9 |
| Comfortable days | 0 | 0 | 3 |
| Daylight | 14.1 h | 13.3 h | 12.4 h |
Highs change by -2°F from July and -3°F into September.
Nearby alternatives in August
- Warmer: Columbia, SC106 mi · high 94°F · 10 wet days
- Drier: Raleigh, NC220 mi · high 89°F · 8 wet days
How Charleston ranks in August
- Normal high186th warmest of 378 cities; 4th of 5 in South Carolina
- Wet days318th driest of 378
- Comfortable days251st most of 341
What to pack for Charleston in August
- Light, breathable clothing – highs near 86°F and about 30 muggy days
- A rain jacket or umbrella – rain on about 12 days
- A swimsuit – about 20 beach days
Heating and cooling
August has 0 heating degree days and 510 cooling degree days (base 65°F), 13% of the year's total heating and cooling demand.
Questions
How hot is Charleston in August?
The normal high is 86°F and the normal low is 77°F. From 1991 to 2020 the hottest August reading was 103°F (August 1, 1999).
Does it rain a lot in Charleston in August?
About 12 days in August have at least 0.01 in of precipitation, and the normal total is 6.1 in. The wettest August in 1991-2020 was in 1992 (14.2 in); the driest was in 1998 (1.5 in).
Is August a good time to visit Charleston?
August ranks 12th of 12 months on our comfort score for Charleston (45 out of 100). It has almost no comfortable days and about 7 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.