Climate of South Carolina
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File:Köppen Climate Types South Carolina.png of South Carolina, using 1991–2020 climate normals.]]
South Carolina has a humid subtropical climate, with hot summers throughout most of the state. But, an exception does occur in the Blue Ridge Mountains, as outlier pockets of an Oceanic Climate do exist. Mild winters predominate in the eastern and southern part of the state, but cool to occasionally cold winters are the standard in the northwestern area of the state, especially areas at or above 600 feet in elevation. On average, between {{convert|40|and|80|in|mm}} of precipitation falls annually across the state, potentially even in excess of 100 inches in portions of the Appalachian temperate rainforest. Tropical cyclones, and afternoon thunderstorms due to hot and humid conditions, contribute to precipitation during the summer and sometimes fall months, while extratropical cyclones contribute to precipitation during the fall, winter, and spring months. The coast experiences nearly all of their tropical weather impacts from storms coming directly from the Atlantic coast. The northwestern area of the state can receive impacts from both Atlantic basin storms moving westward from the coast and also occasionally very heavy rainfall and flooding from storms originating from the Gulf of Mexico that move inland towards the northeast after making landfall from the Florida Panhandle to Louisiana.
Tornadoes happen mostly in the spring, with a secondary peak in November. Hail and damaging winds often occur in summertime thunderstorms. Tornadoes are very uncommon in the summer unless a tropical disturbance were to spawn one.
Temperatures
The USDA Hardiness Zones for South Carolina range from Zone 7B (5°F to 10°F) in the extreme northwest portion of the state, to Zone 9B (25°F to 30°F) along the southeastern coast.
South Carolina has a humid subtropical climate (Köppen climate classification Cfa), although high elevation areas in the "Upstate" area have less subtropical characteristics than areas on the Atlantic coastline. In the summer, South Carolina is hot and humid with temperatures during the day averaging near {{convert|90|F|C}} across most of the state with overnight lows near {{convert|70|F|C}}. Winter temperatures are much less uniform. Coastal areas of the state have very mild winters with high temperatures averaging about {{convert|60|F|C}} and overnight lows close to {{convert|38|F|C}}. Further inland in the Piedmont, temperatures average between {{convert|50|F|C}} during the day and {{convert|32|F|C}} at night.
Precipitation
While precipitation is abundant the entire year in almost the entire state, the coastline tends to have a slightly wetter summer, while inland March tends to be the wettest month. During the cold season, extratropical cyclones is the main cause of precipitation, while during the summer, tropical cyclones and thunderstorms forming due to afternoon heating are the main causes of precipitation. A lee side rain shadow from the Appalachian Mountains lowers annual precipitation across central portions of the state.South Carolina State Climatology Office. [http://www.dnr.sc.gov/climate/sco/ClimateData/cli_sc_climate.php South Carolina Climate.] Retrieved on 2008-03-18. Inland sections average {{convert|40|in|mm}} to {{convert|50|in|mm}} of rainfall, while near the coast {{convert|50|in|mm}} to {{convert|60|in|mm}}, and the Piedmont receives {{convert|70|in|mm}} to {{convert|80|in|mm}} of precipitation.National Atlas.gov. [http://www.nationalatlas.gov/printable/images/preview/precip/pageprecip_sc3.gif Average annual precipitation for South Carolina.] {{webarchive|url=https://web.archive.org/web/20080816183854/http://www.nationalatlas.gov/printable/images/preview/precip/pageprecip_sc3.gif |date=2008-08-16 }} Retrieved on 2008-03-08. Winter precipitation is determined in large by the El Niño-Southern Oscillation. During El Niño events, the jet stream is further south and east across the U.S., thus leading to cooler and wetter winters in South Carolina, while La Niña keeps the jet stream further north and west causing warmer and drier winters.
| class="wikitable" style="font-size: 95%;" width=760px |
! width="200" | Event | width="150" | Measurement | width="150" | Date | width="100" | Location | width = "100" | County |
| Most precipitation in a year for a single area | {{convert|123.45|in|mm|0}} | 2018 {{cite web |url=http://www.dnr.sc.gov/news/2019/may/may2_recordrainfall.php|title=New Record Annual Rainfall Total Set in South Carolina|access-date= 4 May 2019}} | Walhalla State Fish Hatchery | Oconee |
| Least precipitation in a year for a single area | {{convert|22.69|in|cm|0}}{{citation needed|date=June 2021}} | ? |
=Snowfall and ice=
File:South Carolina Snow Plow.png Snow Plow in Columbia, February 2014]]
File:2014 Southeastern Winter Storm Pax 140213-Z-XH297-006.jpg, 2014]]
Annual snowfall across South Carolina varies greatly in frequency and amounts, from being quite rare with little to no accumulation in the southern coastal areas to being very common annually with 2 to 3 small snowfall events in the Upstate, particularly along and north of Interstate 85, which essentially is built along the 850 to 900 feet elevation contour. In the southern coastal area near and below Charleston, several years might pass without any measurable snowfall. In the Greenville, Spartanburg, and Anderson areas, total annual amounts range from 2 to 5 inches, with occasional annual totals reaching 8 or more inches (cumulatively). A year without at least one snow event in the Upstate is quite unusual. The Midlands is the least predictable area of the state in experiencing snowfall events. About 5 out of every 10 years, the region will have no snowfall at all; however in the 5 out of 10 years that the region receives snow, the accumulations are anywhere from under an inch to occasionally as much as 4 to 5 inches. The snowiest location in the state, above 2,000 feet in elevation, averages {{convert|12|in|cm}} of snow a year in the Blue Ridge Escarpment area. Freezing rain is more common than snow around and southeast of Columbia. Along the southern coastal barrier islands, frozen precipitation of any type is very rare, with only a few snow events on record.
=Tropical cyclones=
File:Hugo 1989-09-21 1900Z.png approaching South Carolina on September 21, 1989]]
The state is prone to tropical cyclones. This is an annual concern during hurricane season, which is from June through November. The peak time of vulnerability for the southeast Atlantic coast is from early August to early October when tropical cyclone frequency is highest.National Hurricane Center. [http://www.nhc.noaa.gov/gifs/peakofseason.gif Graphic showing seasonal activity by date.] Retrieved on 2008-03-18. Major hurricanes can impact the Palmetto state, though there are no category 5 impacts on record.Eric S. Blake, Edward N. Rappaport, and Chris Landsea. [http://www.nhc.noaa.gov/pdf/NWS-TPC-5.pdf The Deadliest, Costliest, and Most Intense United States Tropical Cyclones From 1851 to 2006 (and other frequently requested hurricane facts).] Two of the stronger hurricanes to strike South Carolina in recent times are Hurricane Hazel (1954) and Hurricane Hugo (1989), which were of category 4 strength. For weaker systems, rainfall and spin-up tornadoes in the outer bands are the main impacts to the state. The wettest known tropical cyclone to impact South Carolina was a tropical depression named Jerry in 1995 which stalled nearby and had previously been a tropical storm across Florida.National Hurricane Center. [http://www.nhc.noaa.gov/tracks1851to2007_atl_reanal.txt Atlantic Hurricane Track Database.] Retrieved on 2008-03-18. Jerry brought nearly {{convert|19|in|mm}} of rainfall to upstate South Carolina.David M. Roth. [http://www.wpc.ncep.noaa.gov/tropical/rain/jerry1995filledrainblk.gif Tropical Storm Jerry Color-Filled Rainfall Graphic.] Retrieved on 2008-03-18.
| class="wikitable" style="font-size: 95%;" |
! width="200" | Event | width="150" | Measurement | width="150" | Date | width="100" | Location | width = "100" | County |
| Wettest tropical cyclone | {{convert|17.00|in|mm|0}} | Tropical Storm Jerry (1995) | Antreville | Abbeville |
=Thunderstorms and tornadoes=
South Carolina averages around 64 days of thunderstorm activity per year. Most thunderstorms occur during the summer. South Carolina is vulnerable to tornadoes. Some notable tornadoes have struck South Carolina and the state averages around 14 tornadoes annually.National Climatic Data Center. [http://www.ncdc.noaa.gov/img/climate/research/tornado/small/avgt5304.gif Annual average number of tornadoes.] Retrieved on 2006-10-24. There have been no F-5/EF-5 tornadoes on record but over a dozen F-4/EF-4 tornadoes have occurred in many counties in South Carolina.
Monthly normals and extremes for select cities
{{Greenville, South Carolina weatherbox}}
{{Weather box |
|location = Myrtle Beach (1991−2020 normals, extremes 1931–present)
|single line = Y
| Jan record high F = 81
| Feb record high F = 86
| Mar record high F = 88
| Apr record high F = 92
| May record high F = 99
| Jun record high F = 104
| Jul record high F = 101
| Aug record high F = 104
| Sep record high F = 99
| Oct record high F = 93
| Nov record high F = 86
| Dec record high F = 84
|year record high F = 104
| Jan high F = 55.5
| Feb high F = 57.8
| Mar high F = 63.7
| Apr high F = 71.5
| May high F = 78.8
| Jun high F = 84.5
| Jul high F = 87.4
| Aug high F = 86.5
| Sep high F = 83.0
| Oct high F = 75.6
| Nov high F = 66.4
| Dec high F = 58.6
| year high F = 72.4
| Jan mean F = 44.5
| Feb mean F = 46.6
| Mar mean F = 52.7
| Apr mean F = 61.1
| May mean F = 69.3
| Jun mean F = 76.2
| Jul mean F = 79.5
| Aug mean F = 78.3
| Sep mean F = 74.0
| Oct mean F = 64.7
| Nov mean F = 54.3
| Dec mean F = 47.4
| year mean F = 62.4
| Jan low F = 33.6
| Feb low F = 35.5
| Mar low F = 41.8
| Apr low F = 50.6
| May low F = 59.7
| Jun low F = 67.9
| Jul low F = 71.6
| Aug low F = 70.0
| Sep low F = 65.0
| Oct low F = 53.8
| Nov low F = 42.2
| Dec low F = 36.3
| year low F = 52.3
| Jan record low F = 10
| Feb record low F = 9
| Mar record low F = 18
| Apr record low F = 25
| May record low F = 36
| Jun record low F = 48
| Jul record low F = 54
| Aug record low F = 54
| Sep record low F = 43
| Oct record low F = 25
| Nov record low F = 16
| Dec record low F = 10
|year record low F = 9
| precipitation colour = green
| Jan precipitation inch = 3.43
| Feb precipitation inch = 3.76
| Mar precipitation inch = 3.71
| Apr precipitation inch = 3.38
| May precipitation inch = 3.80
| Jun precipitation inch = 4.85
| Jul precipitation inch = 6.61
| Aug precipitation inch = 6.27
| Sep precipitation inch = 6.77
| Oct precipitation inch = 4.11
| Nov precipitation inch = 3.06
| Dec precipitation inch = 3.81
|year precipitation inch = 53.56
|source 1 = NOAA{{cite web
| url = https://w2.weather.gov/climate/xmacis.php?wfo=ilm
| title = NowData – NOAA Online Weather Data
| publisher = National Oceanic and Atmospheric Administration
| access-date = May 14, 2021}}
{{cite web
| url = https://www.ncei.noaa.gov/access/services/data/v1?dataset=normals-monthly-1991-2020&startDate=0001-01-01&endDate=9996-12-31&stations=USC00386153&format=pdf
| publisher = National Oceanic and Atmospheric Administration
| title = Station: Myrtle Beach, SC
| work = U.S. Climate Normals 2020: U.S. Monthly Climate Normals (1991–2020)
| access-date = May 14, 2021}}
}}
{{Charleston, South Carolina weatherbox}}
=Statewide climate data=
{{Weather box
|single line = y
|location = South Carolina
|Jan record high F = 88
|Feb record high F = 89
|Mar record high F = 99
|Apr record high F = 99
|May record high F = 106
|Jun record high F = 113
|Jul record high F = 110
|Aug record high F = 110
|Sep record high F = 111
|Oct record high F = 103
|Nov record high F = 93
|Dec record high F = 89
|Jan record low F = -19
|Feb record low F = -11
|Mar record low F = -8
|Apr record low F = 17
|May record low F = 28
|Jun record low F = 37
|Jul record low F = 45
|Aug record low F = 45
|Sep record low F = 28
|Oct record low F = 16
|Nov record low F = -1
|Dec record low F = -6
|source = {{cite web|url=http://myscmap.sc.gov/climate/sco/ClimateData/cli_table_temp_extremes.php|title=South Carolina Monthly Temperature Extremes}}
}}
Climate change
{{Excerpt|Climate change in South Carolina|only=paragraphs}}
See also
Notes
{{notelist}}