May Weather in Jamestown, Saint Helena, Ascension and Tristan da Cunha

Last updated: August 31, 2025

In May, the average temperature in Jamestown, Saint Helena, Ascension and Tristan da Cunha is a pleasant 23°C (73°F). Expect lows of 21°C (70°F) and highs reaching 24°C (76°F). While enjoying the mild weather, keep in mind that there is a possibility of 12 mm (0.5 in) of precipitation over about 3 days. The average humidity hovers around 78%, adding a touch of warmth to the experience.

May Temperature in Jamestown

In May in Jamestown, the average temperature is a pleasant 23°C (73°F). Maximums can reach up to 24°C (76°F), while minimums can drop to around 21°C (70°F). This mild climate makes it an ideal time for traveling and enjoying outdoor activities.

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

The chart illustrates May temperature patterns in Jamestown, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Jamestown, May typically has an average temperature of 23°C (73°F), with highs reaching up to 24°C (76°F) and lows dropping to around 21°C (70°F).

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

May Precipitation in Jamestown

In Jamestown in May, the precipitation amount is 12 mm (0.5 in) during a span of 3 days.

May Precipitation Trends in Jamestown

The chart displays monthly precipitation patterns in Jamestown, 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 Jamestown, May typically receives around 12 mm (0.5 inches) of precipitation spread over approximately 3 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 Jamestown

In Jamestown in May, humidity is 78%. With an average temperature of 23°C (73°F), this humidity feels like a warm, sticky embrace, making outdoor activities a little challenging but still enjoyable for travelers who appreciate a tropical atmosphere.

May Average Humidity in Jamestown

This chart illustrates the average monthly humidity levels in Jamestown, 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 Jamestown is approximately 78%, 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 Jamestown

In Jamestown in May, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Jamestown.

Maximum UV Index Levels in Jamestown for May

The chart shows the monthly maximum UV Index (UVI) for Jamestown 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 Jamestown typically reaches 9, which falls under the very high exposure category.

Data source: Jamestown 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 Jamestown Compares to Other Months

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

This table compares monthly weather conditions in Jamestown, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	23°C (73°F)	10 mm (0.4 inches)	79%	extreme
February Weather	24°C (75°F)	12 mm (0.5 inches)	81%	extreme
March Weather	24°C (76°F)	16 mm (0.6 inches)	82%	extreme
April Weather	24°C (75°F)	14 mm (0.6 inches)	81%	extreme
May Weather	23°C (73°F)	12 mm (0.5 inches)	78%	very high
June Weather	22°C (71°F)	14 mm (0.5 inches)	74%	very high
July Weather	21°C (69°F)	12 mm (0.5 inches)	75%	very high
August Weather	20°C (68°F)	14 mm (0.6 inches)	76%	very high
September Weather	20°C (67°F)	13 mm (0.5 inches)	78%	extreme
October Weather	19°C (67°F)	11 mm (0.4 inches)	80%	extreme
November Weather	20°C (68°F)	10 mm (0.4 inches)	81%	extreme
December Weather	21°C (70°F)	10 mm (0.4 inches)	80%	extreme