May Weather in Charleston, United States

Last updated: June 24, 2025

In May, the average temperature in Charleston, United States is a pleasant 19°C (66°F). Expect a range with minimums dipping to 1°C (34°F) and maximums soaring up to 32°C (90°F). Rainfall is notable, with 159 mm (6.3 in) expected over 17 days, contributing to an average humidity of 82%.

May Temperature in Charleston

In May in Charleston, the average temperature is 19°C (66°F). Maximums can reach 32°C (90°F) and minimums can be as low as 1°C (34°F). This variation means that travelers should pack a range of clothing to accommodate both warm days and cooler nights.

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 19°C (66°F), with highs reaching up to 32°C (90°F) and lows dropping to around 1°C (34°F).

Data source: Temperature data for Charleston generated using information from the Copernicus Climate Change Service.

May Precipitation in Charleston

In Charleston in May, the precipitation amount is 159 mm (6.3 in) over a span of 17 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 159 mm (6.3 inches) of precipitation spread over approximately 17 days.

Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

May Humidity in Charleston

In Charleston in May humidity is 82%. With an average temperature of 19°C (66°F), this humidity feels like a warm blanket wrapping around you, making it slightly uncomfortable for traveling as you might find yourself constantly seeking shade or a cool breeze.

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.

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 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, 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 10, which falls under the very high exposure category.

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.
	Temperature	Precipitation	Humidity	UV
January Weather	2°C (37°F)	101 mm (4.0 inches)	88%	moderate
February Weather	5°C (42°F)	152 mm (6.0 inches)	88%	moderate
March Weather	9°C (48°F)	119 mm (4.7 inches)	88%	high
April Weather	13°C (56°F)	134 mm (5.3 inches)	86%	very high
May Weather	19°C (66°F)	159 mm (6.3 inches)	82%	very high
June Weather	22°C (72°F)	154 mm (6.1 inches)	84%	very high
July Weather	25°C (77°F)	124 mm (4.9 inches)	82%	very high
August Weather	23°C (74°F)	114 mm (4.5 inches)	73%	very high
September Weather	21°C (70°F)	103 mm (4.0 inches)	73%	very high
October Weather	16°C (61°F)	117 mm (4.6 inches)	81%	high
November Weather	8°C (46°F)	78 mm (3.1 inches)	89%	moderate
December Weather	5°C (41°F)	124 mm (4.9 inches)	86%	moderate