Charleston weather in May
May in Charleston: warm, a little rain, with clean air — an excellent time to visit.
#4 of 12 months in Charleston · #226 of 604 destinations to visit in May · comfort 84/100 (tier A)
Updated June 2026 · climate normals from ERA5 reanalysis
Charleston climate normals — May
| Daytime high | 26°C / 79°F | 🌤 warm |
|---|---|---|
| Nighttime low | 20°C / 68°F | |
| Feels like (high) | 28°C / 82°F | |
| Rainfall | 65 mm / 2.6 in | 🌦 some rain |
| Rainy days | 9 days | |
| Humidity | 76% | 💦 very humid |
| Dew point | 18°C / 64°F | |
| Sunshine | 11.5 h/day | |
| Daylight | 13.9 h | |
| Wind | 20 km/h / 13 mph | |
| Air quality (US AQI) | 47 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
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Charleston in May — FAQ
- Is May a good time to visit Charleston?
- May in Charleston: warm, a little rain, with clean air — an excellent time to visit. It ranks #4 of 12 months for Charleston on SeasonMap's comfort score (84/100).
- What is the weather like in Charleston in May?
- In May, Charleston averages a daily high of 26.2°C and a low of 19.8°C, with about 65.2 mm of rain over roughly 9 rainy days.
- What is the air quality in Charleston in May?
- Charleston has a mean US Air Quality Index of about 47 in May.