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May Weather in Charleston, United States

Last updated: June 24, 2025

In May, the average temperature in Charleston, United States hovers around 21°C (71°F). Temperatures can vary significantly, with a minimum of 4°C (39°F) and a maximum of 34°C (93°F). Expect around 111 mm (4.4 in) of precipitation over the course of 11 days, contributing to an average humidity of 85%.

May Temperature in Charleston

In May in Charleston, the average temperature is 21°C (71°F), with maximums reaching up to 34°C (93°F) and minimums dropping as low as 4°C (39°F). It's a great time for travelers to experience a pleasant blend of warmth and cooler evenings in Charleston.

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 (71°F), with highs reaching up to 34°C (93°F) and lows dropping to around 4°C (39°F).
JanFebMarAprMayJunJulAugSepOctNovDec434854617076807874645046
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 precipitation amount is 111 mm (4.4 in), occurring over the course of 11 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 111 mm (4.4 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec94165157149111991031269412475129
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 85%. With an average temperature of 21°C (71°F), this humidity feels like a warm, heavy blanket enveloping you, making travel a bit more tiring but also creating an atmosphere rich with the scent of blooming flora and vibrant street life.

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 85%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%86%86%82%85%85%83%76%76%80%88%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.
JanFebMarAprMayJunJulAugSepOctNovDec46810111111109763
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 Weather6°C (43°F)94 mm (3.7 inches)86%moderate
February Weather9°C (48°F)165 mm (6.5 inches)86%high
March Weather12°C (54°F)157 mm (6.2 inches)86%very high
April Weather16°C (61°F)149 mm (5.9 inches)82%very high
May Weather21°C (71°F)111 mm (4.4 inches)85%extreme
June Weather24°C (76°F)99 mm (3.9 inches)85%extreme
July Weather27°C (80°F)103 mm (4.1 inches)83%extreme
August Weather26°C (78°F)126 mm (5.0 inches)76%very high
September Weather24°C (75°F)94 mm (3.7 inches)76%very high
October Weather18°C (65°F)124 mm (4.9 inches)80%high
November Weather10°C (51°F)75 mm (2.9 inches)88%high
December Weather8°C (47°F)129 mm (5.1 inches)88%moderate

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