Reference Data in Charleston 12 indicators covering reference data for Charleston. IndicatorLatest Year10-yr change Rank Cooling and heating degree days - Cities and FUAs — Cooling degree 568.97 Degree days 2025 down 14.3% 179th Cooling and heating degree days - Cities and FUAs — Change in cooling -34.04 Degree days 2025 down 155.8% 1029th Cooling and heating degree days - Cities and FUAs 525.79 Degree days 2025 up 5.4% 1054th Cooling and heating degree days - Cities and FUAs — Change in heating -44.92 Degree days 2025 up 37.4% 173rd Precipitation - Cities and FUAs — Extreme precipitation days 17.92 Days per year 2024 up 5.6% 221st Precipitation - Cities and FUAs — Change in extreme precipitation 2.87 Days per year 2024 up 49.4% 340th Dependency ratio - Cities and FUAs 28.6 Percentage of population aged 15-64 years 2024 up 34.3% 657th Wind threats - Cities and FUAs — Exposure to wind threats 0 Percentage of area 2023 — 273rd Coastal flooding - Cities and FUAs — Built-up area exposure to 0.7983 Percentage of built-up area 2022 up 5.3% 115th Main mode of transport to work - Cities and FUAs — Employed persons 180,924 Persons 2023 up 10.1% 99th Internet speed - Cities and FUAs — Downloading speed -6.7 Percentage of national value 2025 down 39.6% 1086th Internet speed - Cities and FUAs — Uploading speed -22.7 Percentage of national value 2025 down 358.0% 1085th