South Carolina has a humid subtropical climate, classified as Cfa under the Köppen system, across the entire state. That means warm, wet summers, mild winters, and rainfall spread throughout the year. But the state’s geography, stretching from the Blue Ridge Mountains down to the Atlantic coast, creates significant variation in temperature, rainfall, and snowfall depending on where you are.
Temperature Across the State
Summers in South Carolina are hot. Coastal cities like Charleston and inland cities like Columbia regularly see highs in the low to mid 90s°F from June through August, and the state’s all-time record high is 113°F, set in Columbia on June 29, 2012. The mountains in the northwest corner stay noticeably cooler, with summer highs often 10 to 15 degrees lower than the Midlands thanks to the elevation.
Winters are mild by national standards, especially along the coast. Charleston’s average January lows hover around 40°F, while the mountains can dip well below freezing overnight. Hard freezes are uncommon in the Lowcountry but happen regularly in the Upstate from December through February.
Why It Feels Hotter Than the Thermometer Says
The number that really defines a South Carolina summer isn’t temperature. It’s the dew point. During peak summer, dew points along the coast routinely climb into the 73 to 78°F range, which is the threshold where the air feels oppressively sticky. Inland readings run only slightly lower, typically in the low to mid 70s. At those levels, sweat doesn’t evaporate efficiently, and heat index values can push well past 100°F even when the actual air temperature is in the low 90s.
Relief comes occasionally when drier air pushes in. Stations in the Upstate have recorded dew points dropping from 70°F down into the mid 50s during brief dry-air intrusions, which makes a dramatic difference in how the heat feels. But those breaks are temporary, and for most of June through September, high humidity is the baseline across the state.
Rainfall: Heaviest in the Mountains
South Carolina gets rain year-round with no true dry season. Every month averages at least two inches of precipitation everywhere in the state, but rainfall peaks twice a year (March and July) and dips twice (May and November). The distribution across the state, though, is far from even.
The mountains are the wettest part of the state by a wide margin. At the highest elevations, annual rainfall reaches 70 to 80 inches, with Caesars Head in the Blue Ridge topping out at over 79 inches per year. The Foothills get 60 to 70 inches. Moving southeast into the Piedmont, totals drop to 45 to 50 inches. The driest area is the Midlands around Columbia, averaging just 42 to 47 inches annually. The Coastal Plain picks back up slightly, averaging 50 to 52 inches.
This pattern is driven by elevation, soil type, and vegetation. Moisture-laden air moving northwest gets pushed upward by the mountains, squeezing out extra rain at higher elevations. The relatively flat Midlands, sitting in a sort of rain shadow, gets less.
Snow and Winter Weather
Most of South Carolina sees very little snow. The coast and Lowcountry average only a few inches per year at most, and many winters pass with no measurable accumulation at all. Beaufort, near the Georgia border, averages just 0.6 inches of snow annually.
The mountains are a different story. Caesars Head averages nearly 29 inches of snow per year, enough to make winter driving a real concern in the Upstate. The contrast is stark: a nearly 50-fold difference in snowfall between the highest and lowest elevations of the same state. Ice storms occasionally affect the Midlands and Piedmont, and these tend to cause more disruption than snow because the region isn’t built to handle prolonged icy conditions.
Hurricanes and Tropical Storms
South Carolina sits in the path of Atlantic hurricanes, and the risk is concentrated in late summer and early fall. Since record-keeping began in 1851, 41 tropical cyclones have made landfall in the area around Charleston alone, with August and September accounting for the most landfalls (12 each). October brings a secondary risk, and the broader region has seen 309 tropical cyclones track through since 1851.
The earliest landfalls on record have occurred in May, and the latest in October, so the practical window of concern runs about six months. Hurricane Hugo in 1989 and Hurricane Matthew in 2016 are among the most destructive storms in the state’s modern history, causing billions in damage and reshaping how coastal communities think about evacuation and building codes.
Tornadoes and Severe Thunderstorms
Tornado season in South Carolina runs from March through May, earlier than the classic Tornado Alley peak. The state isn’t in the highest-risk zone nationally, but it does see tornadoes each year, often spawned by strong spring cold fronts or, during hurricane season, by the outer bands of tropical systems. Severe thunderstorms with damaging winds and large hail are more common than tornadoes and can occur any time from spring through early fall.
Coastal Flooding and Sea Level Rise
South Carolina’s coastline is low-lying, and flooding is already a regular problem in cities like Charleston, where high tides can push water into downtown streets several times a year. Federal modeling from the U.S. Geological Survey projects worsening flood hazards along the Carolina coast under multiple sea level rise scenarios, ranging from a quarter meter to three meters of rise combined with storm surge from hurricanes of varying intensity.
Even under moderate projections, the combination of rising seas and storm surge would push floodwaters significantly farther inland than current conditions. For coastal residents, this means that properties and infrastructure safe from flooding today may not remain so in coming decades. The effects are compounded by the fact that South Carolina’s coast is also sinking slightly due to natural land subsidence, making relative sea level rise faster than the global average.