Record-High Nighttime Temperatures in Charleston Pose Health Risks

In July 2024 downtown Charleston recorded unprecedented overnight lows of 82 °F to 84 °F, about 25 % higher than the combined total of the previous five years. These readings broke the city’s historic warm‑night records, which all dated before 2000. Meteorologists attribute the surge to a strong El Niño in the Pacific and the urban‑heat‑island effect created by asphalt and concrete that retain heat after sunset.

The sustained heat has tangible health consequences. The South Carolina Department of Public Health reported 713 heat‑related emergency‑room visits in July, with older adults, young children and people with chronic illnesses most vulnerable. The National Weather Service notes that extreme heat is the deadliest weather hazard in the United States, and officials are now paying closer attention to nighttime temperatures when issuing heat alerts.