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Average Weather at Charleston International Airport South Carolina, United States

At Charleston International Airport, the summers are hot and oppressive, the winters are short and cold, and it is wet and partly cloudy year round. Over the course of the year, the temperature typically varies from 40°F to 90°F and is rarely below 27°F or above 96°F.

Climate Summary

coolcomfortablewarmhotwarmcomfortablecoolJanFebMarAprMayJunJulAugSepOctNovDec66%66%44%44%clearovercastprecipitation: 5.2 inprecipitation: 5.2 in2.3 in2.3 inmuggy: 97%muggy: 97%0%0%drydrytourism score: 6.5tourism score: 6.52.32.3
Click on each chart for more information.

Based on the tourism score, the best times of year to visit Charleston International Airport for warm-weather activities are from mid April to late May and from mid September to late October.

Temperature

The hot season lasts for 3.7 months, from May 25 to September 16, with an average daily high temperature above 84°F. The hottest day of the year is July 22, with an average high of 90°F and low of 75°F.

The cool season lasts for 2.9 months, from December 2 to February 27, with an average daily high temperature below 65°F. The coldest day of the year is January 17, with an average low of 40°F and high of 59°F.

Average High and Low Temperature

The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Average Hourly Temperature

Average Hourly Temperature at Charleston International AirportJanFebMarAprMayJunJulAugSepOctNovDec12 AM4 AM8 AM12 PM4 PM8 PM12 AMvery coldcoldcoldcoldcoldcoolcoolwarmhotcomfortablecomfortablevery cold
The average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < very cold < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The shaded overlays indicate night and civil twilight.

Bir Ali Ben Khalifa, Tunisia (4,985 miles away) and Büyükçat, Turkey (6,140 miles) are the far-away foreign places with temperatures most similar to Charleston International Airport (view comparison).

Clouds

At Charleston International Airport, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year at Charleston International Airport begins around September 13 and lasts for 2.9 months, ending around December 10. On October 27, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 66% of the time, and overcast or mostly cloudy 34% of the time.

The cloudier part of the year begins around December 10 and lasts for 9.1 months, ending around September 13. On July 27, the cloudiest day of the year, the sky is overcast or mostly cloudy 56% of the time, and clear, mostly clear, or partly cloudy 44% of the time.

Cloud Cover Categories

Cloud Cover Categories at Charleston International AirportclearercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Oct 2766%Oct 2766%Jul 2744%Jul 2744%Sep 1355%Sep 1355%Dec 1055%Dec 1055%clearmostly cloudyovercastmostly clearpartly cloudy
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds: clear < 20% < mostly clear < 40% < partly cloudy < 60% < mostly cloudy < 80% < overcast.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days at Charleston International Airport varies significantly throughout the year.

The wetter season lasts 3.5 months, from May 30 to September 15, with a greater than 35% chance of a given day being a wet day. The chance of a wet day peaks at 51% on August 5.

The drier season lasts 8.5 months, from September 15 to May 30. The smallest chance of a wet day is 19% on October 30.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 51% on August 5.

Daily Chance of Precipitation

Daily Chance of Precipitation at Charleston International AirportwetdrydryJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Aug 551%Aug 551%Oct 3019%Oct 3019%Jan 125%Jan 125%May 3035%May 3035%Sep 1535%Sep 1535%rain
The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Charleston International Airport experiences significant seasonal variation in monthly rainfall.

Rain falls throughout the year at Charleston International Airport. The most rain falls during the 31 days centered around August 19, with an average total accumulation of 5.2 inches.

The least rain falls around November 11, with an average total accumulation of 2.3 inches.

Average Monthly Rainfall

Average Monthly Rainfall at Charleston International AirportJanFebMarAprMayJunJulAugSepOctNovDec0 in2 in4 in6 in8 in10 inAug 195.2 inAug 195.2 inNov 112.3 inNov 112.3 inMar 23.3 inMar 23.3 inMay 52.5 inMay 52.5 in
The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average liquid-equivalent snowfall.

Sun

The length of the day at Charleston International Airport varies significantly over the course of the year. In 2017, the shortest day is December 21, with 9 hours, 59 minutes of daylight; the longest day is June 21, with 14 hours, 19 minutes of daylight.

Hours of Daylight and Twilight

Hours of Daylight and Twilight at Charleston International AirportJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 6 minMar 2012 hr, 6 minMar 2014 hr, 19 minJun 2114 hr, 19 minJun 2112 hr, 8 minSep 2212 hr, 8 minSep 229 hr, 59 minDec 219 hr, 59 minDec 21nightnightday
The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise is at 6:11 AM on June 11, and the latest sunrise is 1 hour, 30 minutes later at 7:40 AM on November 4. The earliest sunset is at 5:13 PM on December 4, and the latest sunset is 3 hours, 19 minutes later at 8:32 PM on June 29.

Daylight saving time (DST) is observed at Charleston International Airport during 2017, starting in the spring on March 12, lasting 7.8 months, and ending in the fall on November 5.

Sunrise & Sunset with Twilight and Daylight Saving Time

Sunrise & Sunset with Twilight and Daylight Saving Time at Charleston International AirportJanFebMarAprMayJunJulAugSepOctNovDec2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 116:11 AMJun 116:11 AM8:32 PMJun 298:32 PMJun 29Dec 45:13 PMDec 45:13 PM7:40 AMNov 47:40 AMNov 4Mar 12DSTMar 12DSTDSTNov 5DSTNov 5daynightnightnightnightSolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day over the course of the year 2017. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight saving time are indicated by the 'DST' labels.

Humidity

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

Charleston International Airport experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 5.5 months, from May 5 to October 20, during which time the comfort level is muggy, oppressive, or miserable at least 25% of the time. The muggiest day of the year is July 22, with muggy conditions 97% of the time.

The least muggy day of the year is February 4, when muggy conditions are essentially unheard of.

Humidity Comfort Levels

Humidity Comfort Levels at Charleston International AirportmuggyJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Feb 40%Feb 40%97%Jul 2297%Jul 22May 525%May 525%Oct 2025%Oct 2025%miserablemiserableoppressiveoppressivedrydryhumidhumidmuggymuggycomfortablecomfortable
The percentage of time spent at various humidity comfort levels, categorized by dew point: dry < 55°F < comfortable < 60°F < humid < 65°F < muggy < 70°F < oppressive < 75°F < miserable.

Wind

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed at Charleston International Airport experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 6.3 months, from November 2 to May 13, with average wind speeds of more than 7.7 miles per hour. The windiest day of the year is February 26, with an average hourly wind speed of 9.0 miles per hour.

The calmer time of year lasts for 5.7 months, from May 13 to November 2. The calmest day of the year is August 17, with an average hourly wind speed of 6.4 miles per hour.

Average Wind Speed

Average Wind Speed at Charleston International AirportwindywindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph2 mph4 mph6 mph8 mph10 mph12 mph14 mphFeb 269.0 mphFeb 269.0 mphAug 176.4 mphAug 176.4 mphNov 27.7 mphNov 27.7 mphMay 137.7 mphMay 137.7 mph
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The predominant average hourly wind direction at Charleston International Airport varies throughout the year.

The wind is most often from the west for 2.3 months, from January 8 to March 17, with a peak percentage of 36% on January 20. The wind is most often from the south for 5.3 months, from March 17 to August 27, with a peak percentage of 51% on July 16. The wind is most often from the north for 3.3 months, from September 29 to January 8, with a peak percentage of 36% on January 1.

Wind Direction

Wind Direction at Charleston International AirportWSENJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%westsouthnortheast
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions (north, east, south, and west), excluding hours in which the mean wind speed is less than 1 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Water Temperature

Charleston International Airport is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average water temperature experiences some seasonal variation over the course of the year.

The time of year with warmer water lasts for 3.4 months, from June 14 to September 28, with an average temperature above 79°F. The day of the year with the warmest water is August 5, with an average temperature of 83°F.

The time of year with cooler water lasts for 4.0 months, from December 19 to April 21, with an average temperature below 67°F. The day of the year with the coolest water is March 4, with an average temperature of 63°F.

Average Water Temperature

The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Best Time of Year to Visit

To characterize how pleasant the weather is at Charleston International Airport throughout the year, we compute two travel scores.

The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best times of year to visit Charleston International Airport for general outdoor tourist activities are from mid April to late May and from mid September to late October, with a peak score in the first week of May.

Tourism Score

Tourism Score at Charleston International Airportbest timeJanFebMarAprMayJunJulAugSepOctNovDec02468106.56.52.32.36.46.44.04.0 precipitationprecipitationcloudscloudstemperaturetemperaturetourism score
The tourism score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best times of year to visit Charleston International Airport for hot-weather activities are from mid May to early July and from early August to late September, with a peak score in the first week of September.

Beach/Pool Score

Beach/Pool Score at Charleston International Airportbest timebest timeJanFebMarAprMayJunJulAugSepOctNovDec02468106.06.00.40.45.85.85.25.2 precipitationprecipitationcloudscloudstemperaturetemperaturebeach/pool score
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Methodology

For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.

Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.

Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.

Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.

Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.

Growing Season

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

The growing season at Charleston International Airport typically lasts for 9.2 months (281 days), from around March 1 to around December 7, rarely starting before January 31 or after March 25, and rarely ending before November 15 or after December 30.

Time Spent in Various Temperature Bands and the Growing Season

Time Spent in Various Temperature Bands and the Growing Season at Charleston International Airportgrowing seasonJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%50%Mar 150%Mar 150%Dec 750%Dec 790%Mar 2590%Mar 2590%Nov 1590%Nov 1510%Jan 3110%Jan 3110%Dec 3010%Dec 301%Jan 151%Jan 15Aug 1100%Aug 1100%very coldcoldcoolcomfortablewarmhot
The percentage of time spent in various temperature bands: frigid < 15°F < freezing < 32°F < very cold < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The black line is the percentage chance that a given day is within the growing season.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

Based on growing degree days alone, the first spring blooms at Charleston International Airport should appear around January 23, only rarely appearing before January 14 or after February 8.

Growing Degree Days

Growing Degree Days at Charleston International AirportJanFebMarAprMayJunJulAugSepOctNovDec0°F1,000°F2,000°F3,000°F4,000°F5,000°F6,000°FJan 2390°FJan 2390°FApr 24900°FApr 24900°FJun 41,800°FJun 41,800°FDec 316,156°FDec 316,156°F
The average growing degree days accumulated over the course of the year, with 25th to 75th and 10th to 90th percentile bands.

Solar Energy

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy experiences significant seasonal variation over the course of the year.

The brighter period of the year lasts for 3.0 months, from April 7 to July 7, with an average daily incident shortwave energy per square meter above 5.9 kWh. The brightest day of the year is May 14, with an average of 6.7 kWh.

The darker period of the year lasts for 2.8 months, from November 11 to February 5, with an average daily incident shortwave energy per square meter below 3.5 kWh. The darkest day of the year is December 21, with an average of 2.8 kWh.

Average Daily Incident Shortwave Solar Energy

Average Daily Incident Shortwave Solar Energy at Charleston International AirportbrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh1 kWh2 kWh3 kWh4 kWh5 kWh6 kWh7 kWh8 kWh9 kWhMay 146.7 kWhMay 146.7 kWhDec 212.8 kWhDec 212.8 kWhApr 75.9 kWhApr 75.9 kWhJul 75.9 kWhJul 75.9 kWhFeb 53.5 kWhFeb 53.5 kWh
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of Charleston International Airport are 32.899 deg latitude, -80.040 deg longitude, and 33 ft elevation.

The topography within 2 miles of Charleston International Airport is essentially flat, with a maximum elevation change of 59 feet and an average elevation above sea level of 41 feet. Within 10 miles is essentially flat (151 feet). Within 50 miles contains only modest variations in elevation (509 feet).

The area within 2 miles of Charleston International Airport is covered by artificial surfaces (96%), within 10 miles by artificial surfaces (46%) and herbaceous vegetation (30%), and within 50 miles by water (37%) and trees (34%).

Data Sources

This report illustrates the typical weather at Charleston International Airport, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.

Temperature and Dew Point

Charleston International Airport has a weather station that reported reliably enough during the analysis period that we have included it in our network. When available, historical temperature and dew point measurements are taken directly from this weather station. These records are obtained from NOAA's Integrated Surface Hourly data set, falling back on ICAO METAR records as required.

In the case of missing or erroneous measurements from this station, we fall back on records from nearby stations, adjusted according to typical seasonal and diurnal intra-station differences. For a given day of the year and hour of the day, the fallback station is selected to minimize the prediction error over the years for which there are measurements for both stations.

The stations on which we may fall back include but are not limited to Charleston, Navelexcen; Charleston NAS; Charleston Executive Airport; Berkeley County Airport; Summerville Airport; Lowcountry Regional Airport; Santee Cooper Regional Airport; and Beaufort County Airport.

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for aiports and weather stations are provided by AskGeo.com .

Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.