Climate and Average Weather Year Round at Sumter Airport United States

At Sumter Airport, the summers are hot and muggy, 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 35°F to 90°F and is rarely below 22°F or above 97°F.

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

The hot season lasts for 3.8 months, from May 22 to September 16, with an average daily high temperature above 83°F. The hottest month of the year at Sumter Airport is July, with an average high of 90°F and low of 71°F.

The cool season lasts for 2.9 months, from November 29 to February 26, with an average daily high temperature below 62°F. The coldest month of the year at Sumter Airport is January, with an average low of 36°F and high of 56°F.

At Sumter 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 Sumter Airport begins around August 22 and lasts for 3.1 months, ending around November 25.

The clearest month of the year at Sumter Airport is October, during which on average the sky is clear, mostly clear, or partly cloudy 64% of the time.

The cloudier part of the year begins around November 25 and lasts for 8.9 months, ending around August 22.

The cloudiest month of the year at Sumter Airport is January, during which on average the sky is overcast or mostly cloudy 50% 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 Sumter Airport varies significantly throughout the year.

The wetter season lasts 3.2 months, from May 23 to August 30, with a greater than 34% chance of a given day being a wet day. The month with the most wet days at Sumter Airport is July, with an average of 14.3 days with at least 0.04 inches of precipitation.

The drier season lasts 8.8 months, from August 30 to May 23. The month with the fewest wet days at Sumter 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 Sumter Airport is July, with an average of 14.3 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 50% on July 25.

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. Sumter Airport experiences some seasonal variation in monthly rainfall.

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

The month with the least rain at Sumter Airport is November, with an average rainfall of 2.6 inches.

Snowfall

As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Sumter Airport experiences some seasonal variation in monthly snowfall.

The snowy period of the year lasts for 1.3 months, from December 23 to February 3, with a sliding 31-day snowfall of at least 1.0 inches. The month with the most snow at Sumter Airport is January, with an average snowfall of 1.4 inches.

The snowless period of the year lasts for 11 months, from February 3 to December 23. The least snow falls around July 20, with an average total accumulation of 0.0 inches.

The length of the day at Sumter Airport varies significantly over the course of the year. In 2024, the shortest day is December 21, with 9 hours, 53 minutes of daylight; the longest day is June 20, with 14 hours, 25 minutes of daylight.

The earliest sunrise is at 6:09 AM on June 11, and the latest sunrise is 1 hour, 33 minutes later at 7:42 AM on November 2. The earliest sunset is at 5:12 PM on December 3, and the latest sunset is 3 hours, 25 minutes later at 8:36 PM on June 28.

Daylight saving time (DST) is observed at Sumter 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.

Sumter Airport experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 5.0 months, from May 10 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 Sumter Airport is July, with 28.2 days that are muggy or worse.

The month with the fewest muggy days at Sumter Airport is February, with 0.2 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 Sumter Airport experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 6.1 months, from November 13 to May 16, with average wind speeds of more than 8.0 miles per hour. The windiest month of the year at Sumter Airport is March, with an average hourly wind speed of 9.4 miles per hour.

The calmer time of year lasts for 5.9 months, from May 16 to November 13. The calmest month of the year at Sumter Airport is August, with an average hourly wind speed of 6.6 miles per hour.

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

The wind is most often from the south for 4.7 months, from March 29 to August 19, with a peak percentage of 40% on July 13. The wind is most often from the north for 2.5 months, from October 5 to December 20, with a peak percentage of 33% on October 13. The wind is most often from the west for 3.3 months, from December 20 to March 29, with a peak percentage of 32% on January 1.

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

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 Sumter Airport for hot-weather activities is from late May to mid September, with a peak score in the last week of August.

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 Sumter Airport typically lasts for 7.5 months (231 days), from around March 20 to around November 6, rarely starting before February 28 or after April 12, and rarely ending before October 20 or after November 23.

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 Sumter Airport should appear around February 4, only rarely appearing before January 20 or after February 22.

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 4.2 months, from April 8 to August 14, with an average daily incident shortwave energy per square meter above 5.9 kWh. The brightest month of the year at Sumter Airport is May, with an average of 6.6 kWh.

The darker period of the year lasts for 2.8 months, from November 11 to February 6, with an average daily incident shortwave energy per square meter below 3.4 kWh. The darkest month of the year at Sumter Airport is December, with an average of 2.7 kWh.

For the purposes of this report, the geographical coordinates of Sumter Airport are 33.992 deg latitude, -80.362 deg longitude, and 177 ft elevation.

The topography within 2 miles of Sumter Airport is essentially flat, with a maximum elevation change of 49 feet and an average elevation above sea level of 169 feet. Within 10 miles is essentially flat (338 feet). Within 50 miles contains only modest variations in elevation (732 feet).

The area within 2 miles of Sumter Airport is covered by cropland (37%), trees (36%), artificial surfaces (16%), and herbaceous vegetation (11%), within 10 miles by cropland (45%) and trees (33%), and within 50 miles by trees (47%) and cropland (30%).