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May Weather in Charleston, United States

Last updated: June 24, 2025

In Charleston, United States, the average temperature in May is a pleasant 21°C (70°F). Visitors can expect a range between a cool 6°C (43°F) and a warm 34°C (94°F). During this month, precipitation averages at 197 mm (7.8 in) over 13 days, and the average humidity sits at a high 82%, making the atmosphere feel quite tropical.

May Temperature in Charleston

In May in Charleston, the average temperature is 21°C (70°F), with maximums reaching 34°C (94°F) and minimums dropping as low as 6°C (43°F). This varied climate makes it an ideal destination for travelers looking to experience a mix of warm days and cooler evenings.

May Weather in Charleston: Daily Temperature Highs, Lows, and Averages

The chart illustrates May temperature patterns in Charleston, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Charleston, May typically has an average temperature of 21°C (70°F), with highs reaching up to 34°C (94°F) and lows dropping to around 6°C (43°F).
JanFebMarAprMayJunJulAugSepOctNovDec414555607078828076635146
Data source: Temperature data for Charleston generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

May Precipitation in Charleston

In Charleston in May, the total precipitation amount is 197 mm (7.8 in), occurring over the course of 13 days.

May Precipitation Trends in Charleston

The chart displays monthly precipitation patterns in Charleston, with values for each month alongside May’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how May’s conditions compare to those of other months. In Charleston, May typically receives around 197 mm (7.8 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec8011613116119710987125591137690
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in Charleston

In Charleston in May, humidity is 82%. With an average temperature of 21°C (70°F), this humidity feels like a warm, sticky embrace that can quickly lead to discomfort for travelers, making outdoor activities less enjoyable and requiring frequent breaks for hydration.

May Average Humidity in Charleston

This chart illustrates the average monthly humidity levels in Charleston, with May’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In May, average humidity in Charleston is approximately 82%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%79%77%78%82%81%75%61%59%69%82%88%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Charleston

In Charleston in May, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in Charleston.

Maximum UV Index Levels in Charleston for May

The chart shows the monthly maximum UV Index (UVI) for Charleston in May, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In May, the maximum UV index in Charleston typically reaches 11, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec46810111111109754
Data source: Charleston May UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How May Weather in Charleston Compares to Other Months

Weather in Charleston varies notably across the year, with each month offering distinct climate conditions. This page compares May’s weather to other months in Charleston, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Charleston, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather5°C (41°F)80 mm (3.1 inches)82%moderate
February Weather7°C (45°F)116 mm (4.6 inches)79%high
March Weather13°C (55°F)131 mm (5.1 inches)77%very high
April Weather16°C (61°F)161 mm (6.3 inches)78%very high
May Weather21°C (70°F)197 mm (7.8 inches)82%extreme
June Weather26°C (78°F)109 mm (4.3 inches)81%extreme
July Weather28°C (82°F)87 mm (3.4 inches)75%extreme
August Weather27°C (80°F)125 mm (4.9 inches)61%very high
September Weather25°C (76°F)59 mm (2.3 inches)59%very high
October Weather17°C (64°F)113 mm (4.5 inches)69%high
November Weather10°C (51°F)76 mm (3.0 inches)82%moderate
December Weather8°C (47°F)90 mm (3.5 inches)87%moderate

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