Charleston County Climate
Charleston County, South Carolina
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
66.1°F
Annual Precip
51.2"
Annual Snowfall
0.3"
Extreme Heat Days
49
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
9a
Minimum winter temperature range for plant survival
6,218
Excellent for heat-loving crops
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Charleston County
Climate Verdict
Charleston County has a warm, averaging 66.1°F year-round, moderately wet with 51.2 inches of annual precipitation, occasional hot days — 48.949999999999996 per year above 90°F, light snow averaging 0.3 inches per year. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are mild, with January temperatures averaging 49.1°F. summers are hot, with July averaging 81.9°F. The 33°F seasonal variation provides noticeable but manageable change.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for Charleston County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Charleston County is 3.2°F warmer than the South Carolina statewide average of 62.8°F, it is somewhat wetter than average for South Carolina.
Climate Profile
About Charleston County Weather
A Coastal Hub Warmer Than Most
Charleston County maintains a warm annual average temperature of 66.1°F, far exceeding the national median. This subtropical climate remains consistently mild compared to the broader United States. The county experiences a humid environment driven by its coastal location.
Well Above the South Carolina Average
The county's average temperature sits more than three degrees higher than the South Carolina state average of 62.8°F. This makes Charleston one of the warmest regions in the state. Its coastal proximity prevents the deeper temperature drops seen in the Upstate.
Warmer and Wetter Than Colleton
Charleston averages 66.1°F, outpacing neighboring Colleton County's 64.8°F. Rainfall here reaches 51.2 inches annually, exceeding the state average of 48.9 inches. Residents enjoy slightly more tropical conditions than their inland peers.
Endless Summers and Negligible Snow
Summer temperatures peak at an average of 81.9°F in July, while extreme heat days occur 49 times per year. Winter is mild with a 50.9°F average and a rare 0.3 inches of annual snowfall. The transition between seasons is often subtle and brief.
Prioritize Humidity Control and Light Gear
High annual precipitation of 51.2 inches requires robust drainage and moisture control for homes. HVAC systems should be optimized for cooling rather than heating to handle the 49 extreme heat days. Lightweight, breathable clothing is the standard for most of the year.
Frequently Asked Questions
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Data sources: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020. Forecast and alert data from National Weather Service API. Air quality data from Open-Meteo.
Climate normals are 30-year averages of weather variables. Station data is aggregated to county level. Forecasts and alerts are fetched live and may change frequently. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.