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    Updated: 01/10/27

NOAA National Centers
for Environmental Information

State Climate Summaries

SOUTH CAROLINA

Key Messages   Narrative   Downloads  

South Carolina State House
Photo by geraldbrazell

Key Message 1

Average temperature for South Carolina has increased about 0.5°F since the early 20th century, less than half that of the United States as a whole. Under a higher emissions pathway, historically unprecedented warming is projected by the end of the 21st century, including increases in extreme heat events.

Key Message 2

Future changes in precipitation are uncertain, but extreme precipitation is projected to increase. In addition, projected increases in temperature will likely increase the intensity of naturally occurring droughts.

Key Message 3

Sea level has risen by 1.3 inches per decade at Charleston since reliable record keeping began in 1921, nearly double the global sea level rise. Global sea level is projected to rise another 1 to 4 feet by 2100, with greater rises for South Carolina. Rising sea levels pose widespread and continuing threats to both natural and built environments in coastal South Carolina.

A Multitude of Evening Colors
Photo by Fran Trudeau

SOUTH CAROLINA

South Carolina’s geographic position at subtropical latitudes and along the southeastern coast of the North American continent adjacent to the Atlantic Ocean gives it a humid climate with hot summers and mild winters. The Appalachian Mountains to the north and west tend to partially shield the state from cold air masses approaching from the northwest, making for somewhat milder winters than locations to the west of the mountains. However, these mountains are not high enough to fully block these air masses and occasional periods of very cold conditions do occur. Clockwise circulation of air around a semi-permanent high pressure system in the North Atlantic Ocean (the “Bermuda High”) provides a persistent flow of warm, moist from the Atlantic during the warmer half of the year. The annual average temperature varies across the state from the mid-50s (°F) in the mountains to the mid-60s (°F) along the coast. During January, average temperatures range from 40°F in the north to around 47°F in the Lowcountry. Similar northwest to southeast temperature gradients also occur in the summer, with average temperatures in July ranging from 76°F in the north, to 82°F in the Midlands and coastal Lowcountry.

   

Figure 1

Observed and Projected Temperature Change
Figure 1: Observed and projected changes (compared to the 1901–1960 average) in near-surface air temperature for South Carolina. Observed data are for 1900–2014. Projected changes for 2006–2100 are from global climate models for two possible futures: one in which greenhouse gas emissions continue to increase (higher emissions) and another in which greenhouse gas emissions increase at a slower rate (lower emissions). Temperatures in South Carolina (orange line) have risen by less than 1°F since the beginning of the 20th century. Shading indicates the range of annual temperatures from the set of models. Observed temperatures are generally within the envelope of model simulations of the historical period (gray shading). Historically unprecedented warming is projected during the 21st century. Less warming is expected under a lower emissions future (the coldest years being as warm as the hottest historical year; green shading) and more warming under a higher emissions future (the hottest years being about 10°F warmer than the hottest historical years; red shading). Source: CICS-NC and NOAA NCEI.

Temperatures in South Carolina have increased about 0.5°F since the beginning of the 20th century (Figure 1). The state warmed during the early part of the 20th century and then cooled substantially during the middle of the 20th century. Since then, warming has occurred but only recently have temperatures reached the levels of the 1930s. The number of extremely hot days (maximum temperature above 100°F) has fluctuated near the statewide average of 3 days per year since the 1990s (Figure 2a), following very high numbers in the 1930s and early 1950s and a period of below average numbers from the late 1950s to the late 1970s. Over the past 30 years (1984–2014), residents in the state capital of Columbia have experienced an average of 3.5 days per year with high temperatures exceeding 100°F, compared to a yearly average of 2.3 days between 1953 and 1983. In the very hot summers of 2015 and 2016, the number of days exceeding 100°F was 10 and 16, respectively, well above average. Very warm nights (minimum temperature above 75°F) have generally been above average since the early 1980s, with the highest 5-year average occurring during the most recent 2010–2014 period (Figure 3). The number of days below freezing (maximum temperature below 32°F) has been below average since the early 1990s (Figure 2b).

   

Figure 2a

2a
   

Figure 2b

2b
   

Figure 2c

2c
   

Figure 2d

2d
Figure 2: The observed (a) number of extremely hot days (maximum temperature above 100°F), (b) number of days below freezing (maximum temperature below 32°F), (c) annual precipitation, and (d) number of extreme precipitation events (precipitation greater than 3 inches), averaged over 5-year periods. The values in Figures 2a, 2b, and 2d are averages from all available long-term reporting stations (12 for temperature and 14 for precipitation). The values in Figure 2c are from NCEI’s version 2 climate division dataset. The number of extremely hot days has been close to the long-term average since the 1980s, while the number of days below freezing has been below average since 1990. Annual precipitation and the number of extreme rainfall days has been below average during the 2000s. The dark horizontal lines indicate long-term (1900–2014) average values. Source: CICS-NC and NOAA NCEI.
   
Observed Number of Very Warm Nights
Figure 3: The observed number of very warm nights (minimum temperature above 75°F) for 1900–2014, averaged over 5-year periods; these values are averages from 12 long-term reporting stations. The number of very warm nights has been above average since the early 1980s. The highest number of very warm nights occurred in the most recent 5-year period of 2010–2014, with an average of 8 nights per year, more than double the long-term average. The dark horizontal line is the long-term (1900–2014) average of 3.8 days per year at a typical station. Source: CICS-NC and NOAA NCEI.

Average annual precipitation ranges from 80 inches near Lake Jocassee in the mountains of the far northwest to less than 39 inches at Wateree in the Midlands, the driest part of the state. While isolated mountain areas receive large precipitation amounts, average precipitation for most of the Upstate is 45 to 55 inches. Average precipitation in the rest of the state is mostly 45 to 50 inches in the Midlands and 45 to 55 inches in the coastal Lowcountry. The high amounts of precipitation in the far northwest are due to moist air being forced up the mountains to higher elevations, while the slightly higher amounts along the Coastal Plain are due to sea-breeze front thunderstorms that occur during the summer months.

Annual precipitation has been below average during most years in the 2000s (12 of 16 years during 2000–2015). However, there is no overall trend since the beginning of the 20th century (Figure 2c) and a few years (notably 2003, 2013, and 2015) have been very wet. Since the start of the 21st century, the state has experienced a below normal number of extreme precipitation events (precipitation greater than 3 inches; Figure 2d). Of the last 15 years in South Carolina, 12 have been characterized by warm season drought conditions.

Some of the major storm threats occurring episodically are hurricanes in the summer and fall and severe thunderstorms capable of producing tornadoes in the late winter and spring. The state ranks 23rd in the Nation for annual tornado frequency, with an average of about 24 tornadoes confirmed each year between 2000 and 2014 (compared to the number one state, Texas, with an estimated 127 tornadoes each year). Strong and destructive tornadoes occur two to four times each year. Over the last decade, the state has experienced numerous billion-dollar disaster events involving severe storms, tornado outbreaks, hurricanes, and droughts. One notable event was the 2008 March tornado outbreak consisting of multiple category EF2–EF3 tornadoes occurring in the Columbia area, resulting in more than $45 million in damages.

In early October 2015, torrential rainfall caused catastrophic flooding. The rainfall relieved the moderate to severe drought conditions of summer 2015 and shattered numerous 24-hour and 5-day total rainfall records. The state’s standing 24-hour rainfall record of 14.8 inches set during Hurricane Floyd in Myrtle Beach (September 16, 1999) was broken at White Birch Circle in Columbia, which recorded a 24-hour total of 17.7 inches on October 4th, with 15.1 inches falling in less than 10 hours in the morning hours. The previous record wettest 5-day period of 17.4 inches (Greenville, August 22–26, 1908) was broken at more than 40 locations, with the largest amounts being recorded at Mount Pleasant (Park West) with 27.2 inches (October 2–6); Charleston (Clark Sound) with 23.8 inches (October 1–5); Georgetown County Airport with 23.5 inches (October 1–5); Charleston (James Island) with 22.0 inches (October 2–6); and Folly Beach with 21.5 inches (October 2–6).

Tropical cyclones and hurricanes occur less frequently than severe thunderstorms and tornadoes, but they have more destructive potential. Hurricane Hugo in 1989 was one of the strongest hurricanes (Category 4) in the state’s history, and at that time was one of the costliest Atlantic hurricanes (ranked ninth) ever. Wind speeds up to 120 mph were observed 200 miles inland, and the storm tide reached 20 feet, resulting in extensive damage including severe residential and commercial flooding, loss of life, and power outages, and other essential infrastructure loss. Damages were estimated at $8–$10 billion. Between 1901 and 2009, a total of 27 tropical cyclones made landfall along the coast of South Carolina. Although hurricanes are rare events in coastal South Carolina, Hurricane Hugo demonstrated the state’s vulnerability to hurricanes. Climate models project an increase in the number of the strongest (Category 4 and 5) hurricanes, accompanied by 20% more rainfall, by the end of the 21st century.

Under a higher emissions pathway, historically unprecedented warming is projected by the end of the 21st century (Figure 1). Even under a pathway of lower greenhouse gas emissions, average annual temperatures are projected to most likely exceed historical record levels by the middle of the 21st century. However, there is a large range of temperature increases under both pathways, and under the lower pathway, a few projections are only slightly warmer than historical records.Increases in the number of extremely hot days and decreases in the number of extremely cold days are projected to accompany the overall warming.

Little change in average annual precipitation is projected over the 21st century (Figure 5). However, any increases in temperature will cause more rapid loss of soil moisture during dry spells, increasing the intensity of naturally occurring droughts in the future. The resulting decreases in water availability, exacerbated by population growth, will continue to increase competition for water.

   
Past and Projected Changes in Global Sea Level
Figure 4: Estimated, observed, and possible future amounts of global sea level rise from 1800 to 2100, relative to the year 2000. The orange line at right shows the most likely range of 1 to 4 feet by 2100 based on an assessment of scientific studies, which falls within a larger possible range of 0.66 feet to 6.6 feet. Source: Melillo et al. 2014 and Parris et al. 2012.
 
Projected Change in Annual Precipitation
Figure 5: Projected changes (%) in annual precipitation for the middle of the 21st century compared to the late 20th century under a higher emissions pathway. Hatching represents areas where the majority of climate models indicate a statistically significant change. South Carolina is part of a large area in the Southeast with projected minimal increases in annual precipitation. Source: CICS-NC and NOAA NCEI.

Since 1921, the sea level at Charleston has risen by 1.3 inches per decade, nearly double the global sea level rise of 0.7 inches per decade. Sea level rise is an important concern in South Carolina due to its extensive coastline. The coast includes an abundance of salt marshes and estuaries, as well as natural seaports such as Georgetown and Charleston. Today, more than 800 square miles of coastal land near the Charleston area lie less than 4 feet above the high tide line. Sea level rise has caused an increase in tidal floods associated with nuisance-level impacts. Nuisance floods are events in which water levels exceed the local threshold (set by NOAA’s National Weather Service) for minor impacts. These events can damage infrastructure, cause road closures, and overwhelm storm drains. As sea level has risen along the South Carolina coastline, the number of tidal flood days (all days exceeding the nuisance level threshold) has also increased, with the greatest number occurring in 2015 (Figure 6). Even marginal amounts of sea level rise increase the likelihood of less common flooding events by amplifying tide and storm surge. Global sea level is projected to rise another 1 to 4 feet globally by 2100 as a result of both past and future emissions from human activities (Figure 5) and greater rises are likely for South Carolina following historical trends. Some state-level estimates project a rise of 3.9 feet by 2100 as compared to 2012, after accounting for local effects of land subsidence. Projected sea level rise will likely result in increased coastal flooding, coastal erosion, and disruptions to coastal and estuarine ecosystems.

 
Observed and Projected Annual Number of Tidal Floods for Charleston C
Figure 6: Number of tidal flood days per year for the observed record (orange bars) and projections for two possible futures: lower emissions (light blue) and higher emissions (dark blue) per calendar year for Charleston, SC. Sea level rise has caused an increase in tidal floods associated with nuisance-level impacts. Nuisance floods are events in which water levels exceed the local threshold (set by NOAA’s National Weather Service) for minor impacts, such as road closures and overwhelmed storm drains. The greatest number of tidal flood days (all days exceeding the nuisance level threshold) occurred in 2015 at Charleston. Projected increases are large even under a lower emissions pathway. Near the end of the century, under a higher emissions pathway, some models (not shown here) project tidal flooding nearly every day of the year. To see these and other projections under additional emissions pathways, please see the supplemental material on the State Summaries website (https://stateclimatesummaries.globalchange.org). Source: NOAA NOS
Lead authors:
Jennifer Runkle, Kenneth E. Kunkel
Contributing Authors:
Laura Stevens, Rebekah Frankson, Brooke C. Stewart, and William Sweet
Recommended Citation:
Runkle, J., K. Kunkel, L. Stevens, R. Frankson, B. Stewart, and W. Sweet, 2017: South Carolina State Climate Summary. NOAA Technical Report NESDIS 149-SC, 4 pp.

Resources

  1. Climate Central, cited 2016: Facts and findings: Sea level rise and storm surge for South Carolina, 4pp. [URL]
  2. Climate Central, cited 2016: Sea level rise and coastal flood risk: Summary for Charleston, SC, 4pp. [URL]
  3. DNR, cited 2016: Climate change impacts to natural resources in South Carolina, Department of Natural Resources, 101pp. [URL]
  4. DNR, cited 2016: South Carolina climate, Department of Natural Resources. [URL]
  5. Hayhoe, K., D.J. Wuebbles, D.R. Easterling, D.W. Fahey, S. Doherty, J. Kossin, W. Sweet, R. Vose, and M. Wehner, 2018: Our Changing Climate. In Impacts, Risks, and Adaptation in the United States: Fourth National Climate Assessment, Volume II [Reidmiller, D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. Maycock, and B.C. Stewart (eds.)]. U.S. Global Change Research Program, Washington, DC, USA, pp. 72–144.
  6. Knowlton, K., 2015: Climate change threatens health, Extreme Weather: Record-breaking events in 2011, National Resources Defense Council. [URL]
  7. Kunkel, K.E, L.E. Stevens, S.E. Stevens, L. Sun, E. Janssen, D. Wuebbles, C.E. Konrad II, C.M. Fuhrman, B.D. Keim, M.C. Kruk, A. Billet, H. Needham, M. Schafer, and J.G. Dobson, 2013: Regional Climate Trends and Scenarios for the U.S. National Climate Assessment. Part 2. Climate of the Southeast U.S., NOAA Technical Report NESDIS 142-2, 94 pp. [URL]
  8. Magill, B., 2014. The front lines of climate change: Charleston’s struggle, Climate Central, published January 9th, 2014, retrieved March 15, 2015. [URL]
  9. Melillo, J.M., T.C. Richmond, and G.W. Yohe, eds., 2014: Climate Change Impacts in the United States: The Third National Climate Assessment. U.S. Global Change Research Program, 841 pp. doi: 10.7930/J0Z31WJ2
  10. NOAA, cited 2016: Climate of South Carolina, National Oceanic and Atmospheric Administration. [URL]
  11. Parris, A., P. Bromirski, V. Burkett, D. Cayan, M. Culver, J. Hall, R. Horton, K. Knuuti, R. Moss, J. Obeysekera, A. Sallenger, and J. Weiss, 2012: Global Sea Level Rise Scenarios for the United States National Climate Assessment. NOAA Tech Memo OAR CPO-1, 37 pp., National Oceanic and Atmospheric Administration, Silver Spring, MD. [URL]
  12. SC Department of Parks, cited 2016: [URL]
  13. SC DNR, cited 2016: South Carolina flooding 2015: Interactive Journal of the October Historic Rain and Flooding, South Carolina Department of Natural Resources. [URL]
  14. The White House, cited 2016: The threat of carbon pollution: South Carolina, Fact sheet. [URL]
  15. Vose, R.S., D.R. Easterling, K.E. Kunkel, A.N. LeGrande, and M.F. Wehner, 2017: Temperature changes in the United States. In: Climate Science Special Report: Fourth National Climate Assessment, Volume I [Wuebbles, D.J., D.W. Fahey, K.A. Hibbard, D.J. Dokken, B.C. Stewart, and T.K. Maycock (eds.)]. U.S. Global Change Research Program, Washington, DC, USA, pp. 267-301.
  16. Wiltgen, N., 2015: South Carolina’s catastrophic floods caused by one of the most prolific rainfall events in modern U.S. history, News, published on October 11, 2015 and retrieved March 17, 2015. [URL]
  17. Zervas, C., G. Locke, J. Lubchenco, J.H. Dunnigan, and M. Szabados, 2009: Sea level variations of the United States 1854-2006, NOAA Technical Report NOS CO-OPS 053, 194pp. [URL]

NCICS

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