Climate and Average Weather Year Round at Barnwell Regional Airport South Carolina, United States

At Barnwell Regional Airport, the summers are hot and oppressive, the winters are cold, and it is wet and partly cloudy year round. Over the course of the year, the temperature typically varies from 36°F to 92°F and is rarely below 23°F or above 99°F.

Based on the tourism score, the best times of year to visit Barnwell Regional Airport for warm-weather activities are from mid April to early June and from early September to late October.

The hot season lasts for 3.8 months, from May 20 to September 14, with an average daily high temperature above 85°F. The hottest month of the year at Barnwell Regional Airport is July, with an average high of 92°F and low of 71°F.

The cool season lasts for 3.0 months, from November 28 to February 26, with an average daily high temperature below 65°F. The coldest month of the year at Barnwell Regional Airport is January, with an average low of 37°F and high of 58°F.

At Barnwell Regional Airport, the average percentage of the sky covered by clouds experiences mild seasonal variation over the course of the year.

The clearer part of the year at Barnwell Regional Airport begins around August 23 and lasts for 3.1 months, ending around November 26.

The clearest month of the year at Barnwell Regional Airport is October, during which on average the sky is clear, mostly clear, or partly cloudy 65% of the time.

The cloudier part of the year begins around November 26 and lasts for 8.9 months, ending around August 23.

The cloudiest month of the year at Barnwell Regional Airport is July, during which on average the sky is overcast or mostly cloudy 49% of the time.

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

The wetter season lasts 3.2 months, from May 27 to September 4, with a greater than 35% chance of a given day being a wet day. The month with the most wet days at Barnwell Regional Airport is July, with an average of 14.7 days with at least 0.04 inches of precipitation.

The drier season lasts 8.7 months, from September 4 to May 27. The month with the fewest wet days at Barnwell Regional Airport is November, with an average of 6.1 days with at least 0.04 inches of precipitation.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone at Barnwell Regional Airport is July, with an average of 14.7 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 51% on August 4.

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. Barnwell Regional Airport experiences some seasonal variation in monthly rainfall.

Rain falls throughout the year at Barnwell Regional Airport. The month with the most rain at Barnwell Regional Airport is August, with an average rainfall of 4.2 inches.

The month with the least rain at Barnwell Regional Airport is November, with an average rainfall of 2.4 inches.

The length of the day at Barnwell Regional Airport varies significantly over the course of the year. In 2024, the shortest day is December 21, with 9 hours, 57 minutes of daylight; the longest day is June 20, with 14 hours, 21 minutes of daylight.

The earliest sunrise is at 6:15 AM on June 11, and the latest sunrise is 1 hour, 30 minutes later at 7:45 AM on November 2. The earliest sunset is at 5:17 PM on December 4, and the latest sunset is 3 hours, 21 minutes later at 8:38 PM on June 28.

Daylight saving time (DST) is observed at Barnwell Regional Airport during 2024, starting in the spring on March 10, lasting 7.8 months, and ending in the fall on November 3.

The figure below presents a compact representation of key lunar data for 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases.

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.

Barnwell Regional Airport experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 5.1 months, from May 8 to October 11, during which time the comfort level is muggy, oppressive, or miserable at least 24% of the time. The month with the most muggy days at Barnwell Regional Airport is July, with 28.7 days that are muggy or worse.

The month with the fewest muggy days at Barnwell Regional Airport is February, with 0.3 days that are muggy or worse.

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 Barnwell Regional Airport experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 6.4 months, from November 2 to May 14, with average wind speeds of more than 7.0 miles per hour. The windiest month of the year at Barnwell Regional Airport is March, with an average hourly wind speed of 8.3 miles per hour.

The calmer time of year lasts for 5.6 months, from May 14 to November 2. The calmest month of the year at Barnwell Regional Airport is August, with an average hourly wind speed of 5.6 miles per hour.

The predominant average hourly wind direction at Barnwell Regional Airport varies throughout the year.

The wind is most often from the south for 1.5 months, from May 10 to June 24; for 1.0 weeks, from July 5 to July 12; and for 3.0 weeks, from July 23 to August 13, with a peak percentage of 37% on July 11. The wind is most often from the west for 1.6 weeks, from June 24 to July 5; for 1.6 weeks, from July 12 to July 23; and for 5.5 months, from November 27 to May 10, with a peak percentage of 37% on July 14. The wind is most often from the east for 2.9 months, from August 13 to November 11, with a peak percentage of 40% on September 5.

To characterize how pleasant the weather is at Barnwell Regional 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 Barnwell Regional Airport for general outdoor tourist activities are from mid April to early June and from early September to late October, with a peak score in the last week of September.

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Barnwell Regional Airport for hot-weather activities is from late May to late September, with a peak score in the first week of September.

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.

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 Barnwell Regional Airport typically lasts for 7.9 months (241 days), from around March 18 to around November 14, rarely starting before February 26 or after April 8, and rarely ending before October 25 or after December 7.

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 Barnwell Regional Airport should appear around January 29, only rarely appearing before January 15 or after February 15.

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 4.1 months, from April 8 to August 10, with an average daily incident shortwave energy per square meter above 5.9 kWh. The brightest month of the year at Barnwell Regional Airport is May, 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 month of the year at Barnwell Regional Airport is December, with an average of 2.8 kWh.

For the purposes of this report, the geographical coordinates of Barnwell Regional Airport are 33.260 deg latitude, -81.381 deg longitude, and 230 ft elevation.

The topography within 2 miles of Barnwell Regional Airport contains only modest variations in elevation, with a maximum elevation change of 121 feet and an average elevation above sea level of 220 feet. Within 10 miles also contains only modest variations in elevation (289 feet). Within 50 miles contains only modest variations in elevation (673 feet).

The area within 2 miles of Barnwell Regional Airport is covered by artificial surfaces (43%), trees (31%), and cropland (21%), within 10 miles by trees (53%) and cropland (29%), and within 50 miles by trees (53%) and cropland (27%).