Climate and Average Weather Year Round in Summerville United States

In Summerville, 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 38°F to 91°F and is rarely below 25°F or above 96°F.

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

The hot season lasts for 3.7 months, from May 24 to September 13, with an average daily high temperature above 84°F. The hottest month of the year in Summerville is July, with an average high of 91°F and low of 72°F.

The cool season lasts for 3.0 months, from November 30 to February 27, with an average daily high temperature below 65°F. The coldest month of the year in Summerville is January, with an average low of 39°F and high of 59°F.

In Summerville, 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 in Summerville begins around September 11 and lasts for 2.9 months, ending around December 7.

The clearest month of the year in Summerville 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 December 7 and lasts for 9.1 months, ending around September 11.

The cloudiest month of the year in Summerville is July, during which on average the sky is overcast or mostly cloudy 54% 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 in Summerville varies significantly throughout the year.

The wetter season lasts 3.5 months, from May 28 to September 13, with a greater than 35% chance of a given day being a wet day. The month with the most wet days in Summerville is July, with an average of 15.0 days with at least 0.04 inches of precipitation.

The drier season lasts 8.5 months, from September 13 to May 28. The month with the fewest wet days in Summerville is November, with an average of 6.0 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 in Summerville is July, with an average of 15.0 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. Summerville experiences significant seasonal variation in monthly rainfall.

Rain falls throughout the year in Summerville. The month with the most rain in Summerville is August, with an average rainfall of 5.1 inches.

The month with the least rain in Summerville is November, with an average rainfall of 2.3 inches.

The length of the day in Summerville varies significantly over the course of the year. In 2024, the shortest day is December 21, with 9 hours, 58 minutes of daylight; the longest day is June 20, with 14 hours, 20 minutes of daylight.

The earliest sunrise is at 6:11 AM on June 11, and the latest sunrise is 1 hour, 29 minutes later at 7:40 AM on November 2. The earliest sunset is at 5:13 PM on December 3, and the latest sunset is 3 hours, 20 minutes later at 8:33 PM on June 29.

Daylight saving time (DST) is observed in Summerville 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.

Summerville experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 5.5 months, from May 3 to October 21, during which time the comfort level is muggy, oppressive, or miserable at least 25% of the time. The month with the most muggy days in Summerville is July, with 29.7 days that are muggy or worse.

The month with the fewest muggy days in Summerville is February, with 0.4 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 in Summerville experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 6.4 months, from November 5 to May 16, with average wind speeds of more than 6.5 miles per hour. The windiest month of the year in Summerville is March, with an average hourly wind speed of 7.5 miles per hour.

The calmer time of year lasts for 5.6 months, from May 16 to November 5. The calmest month of the year in Summerville is August, with an average hourly wind speed of 5.4 miles per hour.

The predominant average hourly wind direction in Summerville varies throughout the year.

The wind is most often from the west for 2.3 months, from January 7 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 25, with a peak percentage of 49% on July 15. The wind is most often from the north for 3.4 months, from September 26 to January 7, with a peak percentage of 36% on January 1.

Summerville 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 13 to September 26, with an average temperature above 79°F. The month of the year in Summerville with the warmest water is August, with an average temperature of 83°F.

The time of year with cooler water lasts for 4.1 months, from December 15 to April 19, with an average temperature below 67°F. The month of the year in Summerville with the coolest water is March, with an average temperature of 63°F.

To characterize how pleasant the weather is in Summerville 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 Summerville 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 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 times of year to visit Summerville for hot-weather activities are from mid May to mid July and from late July 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 in Summerville typically lasts for 8.4 months (258 days), from around March 9 to around November 22, rarely starting before February 12 or after April 3, and rarely ending before November 2 or after December 17.

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 in Summerville should appear around January 26, only rarely appearing before January 15 or after February 12.

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 3.1 months, from April 6 to July 9, with an average daily incident shortwave energy per square meter above 5.9 kWh. The brightest month of the year in Summerville 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 5, with an average daily incident shortwave energy per square meter below 3.5 kWh. The darkest month of the year in Summerville is December, with an average of 2.8 kWh.

For the purposes of this report, the geographical coordinates of Summerville are 33.019 deg latitude, -80.176 deg longitude, and 82 ft elevation.

The topography within 2 miles of Summerville is essentially flat, with a maximum elevation change of 69 feet and an average elevation above sea level of 81 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 Summerville is covered by artificial surfaces (77%) and trees (22%), within 10 miles by trees (43%) and artificial surfaces (31%), and within 50 miles by trees (40%) and water (24%).