May weather forecast
Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha

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The Longwood house, an ancient exile residence of Napoleon, in Saint Helena Island, Sanit Helena
The Longwood house, an ancient exile residence of Napoleon, in Saint Helena Island, Sanit Helena

Weather in May

In May, Saint Helena Island, Ascension, and Tristan da Cunha experience a significant change in the weather pattern. The rainfall remains fairly consistent, yielding lush, green landscapes and teeming wildlife. Sea temperatures maintain a pleasing warmth for swimming and other water activities, while the overall temperatures mark the onset of cooler weather. Travelers eagerly anticipate May's vivid sunsets, brought about by the longer hours of daylight. With the reduced hours of daily sunshine from 16 to 14, the days become more pleasant, with less intensity from the heat.

Temperature

The arrival of May sees an average high-temperature of a still agreeable 21°C (69.8°F), hardly diverging from April's 22°C (71.6°F). In Saint Helena Island, the nighttime temperature in May descends gently to an average of 17°C (62.6°F).

Rainfall

In Saint Helena Island, during May, the rain falls for 14 days and regularly aggregates up to 71mm (2.8") of precipitation. Throughout the year, there are 170 rainfall days, and 748mm (29.45") of precipitation is accumulated.

Sea temperature

In Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha, the average seawater temperature in May is 24°C (75.2°F).
Note: A swim in 24°C (75.2°F) waters can be refreshing, especially when factoring in a person's cold tolerance, sunshine, wind, and the overall temperature. As a point of reference, Olympic swimming events are held in 25°C (77°F) to 28°C (82.4°F) waters.

Daylight

In May, the average length of the day in Saint Helena Island is 11h and 22min.
On the first day of the month, sunrise is at 06:34 and sunset at 18:05. On the last day of May, sunrise is at 06:43 and sunset at 17:57 GMT.

Sunshine

The average sunshine in May is 14h.

UV index

In May, the average daily maximum UV index in Saint Helena Island is 9. A UV Index value of 8 to 10 symbolizes a very high threat to health from unprotected exposure to Sun's UV rays for average individuals.
Note: In May, the maximum UV index of 9 suggests these recommendations:
Always use protective measures; unprotected skin might suffer damage in a short span. From 10 a.m. to 4 p.m., when UV radiation is at its strongest, limit direct exposure to the Sun and note that shade structures may not provide full sun protection. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage. When outdoors, it's wise to limit direct sunlight exposure, especially if you have sensitive skin. Always use sunscreen with a minimum 30 SPF. Stay vigilant! UV rays get a boost in intensity due to sand and water reflections.
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Frequently asked questions

What is the usual temperature for Saint Helena Island in May?

In Saint Helena Island, 21°C (69.8°F) is the average high-temperature and 17°C (62.6°F) is the average low-temperature during May.

How many days does it rain in May in Saint Helena Island?

In Saint Helena Island, in May, it is raining for 14 days, with typically 71mm (2.8") of accumulated precipitation.

What is the sea temperature in May in Saint Helena Island?

In May, the average sea temperature in Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha, is 24°C (75.2°F). Depending on a person's sensitivity to cold, with regards to sunshine, wind, and air temperature, a quick swim in 24°C (75.2°F) water may be enjoyable.

What is the average length of the day in May in Saint Helena Island?

The average day length in May is 11h and 22min.

When is the sunrise / sunset in May in Saint Helena Island?

On the first day of May in Saint Helena Island, sunrise is at 06:34 and sunset at 18:05. On the last day of the month, sunrise is at 06:43 and sunset at 17:57 GMT.

How long on average sun shines in May in Saint Helena Island?

The average sunshine duration in May in Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha, is 14h.

What is the UV index reading in May in Saint Helena Island?

In Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha, the average daily maximum UV index in May is 9. A UV Index value of 8 to 10 symbolizes a very high health threat from exposure to the Sun's UV radiation.
Average rainfall days
Average daylight
Average sunshine
Average UV index

Average temperature in May
Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha

Average temperature in May - Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha
  • Average high temperature in May: 21°C

The warmest months (with the highest average high temperature) are February and March (23°C).
The month with the lowest average high temperature is August (17°C).

  • Average low temperature in May: 17°C

The months with the highest average low temperature are February and March (19°C).
The coldest month (with the lowest average low temperature) is August (14°C).

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Average rainfall in May
Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha

Average rainfall in May - Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha
  • Average rainfall in May: 71mm

The wettest month (with the highest rainfall) is March (90mm).
The driest month (with the least rainfall) is November (30mm).

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Average rainfall days in May
Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha

Average rainfall days in May - Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha
  • Average rainfall days in May: 14 days

The months with the highest number of rainy days are June and July (16 days).
The months with the least rainy days are September and December (12 days).

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Average sea temperature in May
Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha

Average sea temperature in May - Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha
  • Average sea temperature in May: 24°C

The best months for swimming (with the highest average sea temperature) are February, March and April (25°C).
The coldest month (with the lowest average sea temperature) is October (20°C).

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Average daylight in May /
Average sunshine in May
Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha

Average daylight in May / Average sunshine in May - Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha
  • Average daylight in May: 11h and 2min

The month with the longest days is December (Average daylight: 13h and 6min).
The month with the shortest days is June (Average daylight: 11h and 12min).

  • Average sunshine in May: 14h

The months with the most sunshine are June and July (Average sunshine: 16h).
The months with the least sunshine are September and December (Average sunshine: 12h).

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Average UV index in May
Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha

Average UV index in May - Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha
  • Average UV index in May: 9

The months with the highest UV index are January, February, March, October, November and December (UV index 12).
The month with the lowest UV index is June (UV index 7).

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Saint Helena Island, Saint Helena, Ascension and Tristan da Cunha

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