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Contents
- The climate of Ascension Island
- The best time to visit Ascension Island
- The worst time to visit Ascension Island
- Spring weather in Ascension Island
- Summer weather in Ascension Island
- Autumn weather in Ascension Island
- Winter weather in Ascension Island
- Weather in January
- Weather in February
- Weather in March
- Weather in April
- Weather in May
- Weather in June
- Weather in July
- Weather in August
- Weather in September
- Weather in October
- Weather in November
- Weather in December
- Frequently asked questions
- Average temperature
- Average humidity
- Average rainfall
- Average rainfall days
- Average sea temperature
- Average daylight
- Average sunshine
- Average UV index
The climate of Ascension Island
Ascension Island, part and parcel of Saint Helena, Ascension, and Tristan da Cunha, sits isolated in the South Atlantic Ocean. According to the Köppen climate classification, this geopolitical entity represents a paradigm of Tropical Rainforest Climate, also known as Af. This climate type is characterized by constant high temperatures throughout the year, abundant rainfall, and lack of a distinct dry season.
The weather of Ascension Island, staying true to its Af climate, doesn't waver drastically in temperature throughout the year. From a low of 22°C (71.6°F) to a high of 31°C (87.8°F), residents can expect the thermometer to stay in this range no matter the month. The Island, however, does garner attention for its abundant rainfall. With an average of 10mm (0.39") to 33mm (1.3") from February to April, this location turns lavish with flora in full bloom.
Ascension Island's ocean temperature adds another facet into its climatic profile. The sea temperature ranges from 24°C (75.2°F) to 28°C (82.4°F), making it comfortable for marine activities throughout the year. The longest daylight is experienced from November to January, peaking at 12.6 hours in December. Conversely, shortest days, with 11.7 hours of daylight, fall between June and July.
Unique to Ascension Island is the considerable UV index. It fluctuates from 12 to 9, suggesting individuals should adopt effective protective measures against harmful UV radiation. Also noteworthy is the relative humidity, fluctuating within 67% to 70%, contributing to the overall perception of warmth on the Island.
The weather of Ascension Island, staying true to its Af climate, doesn't waver drastically in temperature throughout the year. From a low of 22°C (71.6°F) to a high of 31°C (87.8°F), residents can expect the thermometer to stay in this range no matter the month. The Island, however, does garner attention for its abundant rainfall. With an average of 10mm (0.39") to 33mm (1.3") from February to April, this location turns lavish with flora in full bloom.
Ascension Island's ocean temperature adds another facet into its climatic profile. The sea temperature ranges from 24°C (75.2°F) to 28°C (82.4°F), making it comfortable for marine activities throughout the year. The longest daylight is experienced from November to January, peaking at 12.6 hours in December. Conversely, shortest days, with 11.7 hours of daylight, fall between June and July.
Unique to Ascension Island is the considerable UV index. It fluctuates from 12 to 9, suggesting individuals should adopt effective protective measures against harmful UV radiation. Also noteworthy is the relative humidity, fluctuating within 67% to 70%, contributing to the overall perception of warmth on the Island.
The best time to visit Ascension Island
Given the uniform temperature, available sunlight, ultimately the decision to visit Ascension Island boils down to rainfall preferences. The driest months on the Island are from September to January, with an average rainfall between 4mm (0.16") to 7mm (0.28"). This time frame aligns with lower humidity and more sun hours daily, ideal circumstances for outdoor enthusiasts. Ocean temperatures also remain pleasant, hovering between 24°C (75.2°F) to 25°C (77°F), allowing for a comfortable dip into the tropical waters of Ascension Island.
The worst time to visit Ascension Island
On the contrary, the months from February to April could be termed challenging for potential visitors. Throughout these months, the precipitation levels peak, with April witnessing a rainfall average of 33mm (1.3") over four days. The saturated environment during this period might not be conducive for sightseeing and other outdoor activities.
Spring weather in Ascension Island
Despite being situated in the Southern Hemisphere, Ascension Island's spring months — September, October, and November — display similar characteristics to spring in the Northern Hemisphere. The temperature resides around a comfortable range of 28°C (82.4°F) to 30°C (86°F) while humidity slowly recedes from 69% to 68%. Sea temperatures maintain warmth within 24°C (75.2°F) to 26°C (78.8°F), inviting for water-bound activities. However, what truly makes these months feel like spring is the decrease in precipitation, with rainfall standing between 4mm (0.16") to 8mm (0.31").
Summer weather in Ascension Island
Marking the onset of Ascension Island's summer, December introduces marginally cooler temperatures, ranging from 29°C (84.2°F) to 22°C (71.6°F). The trend continues until February, with temperatures barely veering off this course. Rainfall sees a sudden hike from 4mm (0.16") in December to 18mm (0.71") in February. Relative humidity oscillates between 69% to 70% as sea temperatures adaopt a cozy range of 25°C (77°F) to 28°C (82.4°F).
Autumn weather in Ascension Island
The months from March to May are characterized by a slight drop in temperature, hovering between 31°C (87.8°F) and 24°C (75.2°F). Interestingly, rainfall sees a considerable rise during the early part of this period, with 33mm (1.3") in March and 16mm (0.63") in April. Levels later recede to 15mm (0.59") in May. Relative humidity remains around the 69% mark as daylight hours decrease gradually and sea temperature ranges between 28°C (82.4°F) to 26°C (78.8°F).
Winter weather in Ascension Island
In June, the Island welcomes winter weather. The temperature swings between 29°C (84.2°F) and 22°C (71.6°F), providing relatively cooler relief from the consistent highs. Rainfall continues its declining trajectory from 15mm (0.59") in June to 11mm (0.43") in August. Relative humidity shows only a marginal decrease, falling to 68%. Sea temperature drops slightly to an average of 25°C (77°F) in August, whilst daylight hours maintain a consistent span of about 11.7 for the winter season.
Weather in January
Gentle whispers of warm air hover over Ascension Island marking the start of a new year. Compared to December, January weather sees a negligible increase in temperature from 28°C (82.4°F) to 30°C (86°F) as the highest value recorded for the day. Weather in January »
Weather in February
No notable changes away from the mild weather of January, February proceeds along the same lines. Still maintaining its warm trend, the most precipitation is experienced during this month, with rainfall reaching up to 10mm (0.39"). Weather in February »
Weather in March
The tropical allure of Ascension Island can be felt vividly in March. The Island experiences a slight escalation in temperature, and humidity concurrently reduces to 69%. Sun worshippers who wish to tan and laze on the beach will be captivated. Weather in March »
Weather in April
As April strides in, the weather becomes marginally cooler with temperatures dipping slightly. Rainfall significantly escalates, peaking at 33mm (1.3"), becoming the rainiest month of the year in Ascension Island. From gentle drizzles to abrupt showers, the month has it all, creating a nature enthusiast's dream scenery. Weather in April »
Weather in May
Embracing Ascension Island in May means welcoming a subtle change in weather. Peak temperatures remain constant at 31°C (87.8°F), while rainfall levels drop to 16mm (0.63"), inviting more clear days. Verdant landscapes left behind by April rainfall continue to flourish under the warm sun rays. Weather in May »
Weather in June
June presents an appealing balance of warmth, sunshine, and minimal rainfall. Lower temperatures touch 23°C (73.4°F) which creates moderately cooler evenings. Water temperatures recede to 27°C (80.6°F), allowing for soothing swims. Weather in June »
Weather in July
July marks the transition into cooler, more temperate days on Ascension Island. Temperatures drop to an agreeable 29°C (84.2°F) at their peak and nights become cooler. The humidity hovers fairly steadily, providing comfort during outdoor activities. Weather in July »
Weather in August
The calm and balmy August weather in Ascension Island offers a noticeble dip in temperature to 28°C (82.4°F). A steady bout of warm and occasional drizzles that make up to 11mm (0.43") rainfall, rejuvenate the island's ecosystem. Weather in August »
Weather in September
With the advent of September, the weather remains similar to August with no significant drop in temperature. Sunshine hours reduce to 5.5h, making these days slightly shorter. Embrace the beauty of Ascension Island during exciting dawn treks and romantic sunset picnics. Weather in September »
Weather in October
October arrives carrying ample sunlight, averaging about 5.2h of sunshine each day. The temperature remains constant around 28°C (82.4°F), marking stable conditions. Rainfall further recedes to 7mm (0.28"), injecting few rainy days into the monthly forecast. Weather in October »
Weather in November
November, the last month of the spring in Ascension Island, is warm month, with an average temperature fluctuating between 28°C (82.4°F) and 22°C (71.6°F). An excellent water temperature of 25°C (77°F) and only 1 rainfall days, with 4mm (0.16") of accumulated rainfall, makes November a prime for swimming and other water activities. Weather in November »
Weather in December
Ushering in the end of the year, December maintains the calm weather noted in November. Daytime temperatures hover around 29°C (84.2°F) and decrease to 22°C (71.6°F) during nights. A mere 4mm (0.16") of rainfall is measured, resulting in more sun-filled days. Weather in December »
Updated: Jan 26, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the most humid month in Ascension Island?
With an average relative humidity of 70%, January is the most humid month in Ascension Island.
What is the driest month in Ascension Island?
The months with the least rainfall are January, November and December Rain falls for 2 days and accumulates 4mm (0.16") of rain.
How many days does it rain in Ascension Island?
Throughout the year, in Ascension Island, there are 30 rainfall days, and 142mm (5.59") of precipitation is accumulated.
When is the highest UV index in Ascension Island?
The months with the highest UV index in Ascension Island, Saint Helena, Ascension and Tristan da Cunha, are January through April, September through December, with an average maximum UV index of 12.
What is the warmest month in Ascension Island?
During February through May, Ascension Island experiences its peak temperatures, averaging a high-temperature of 31°C (87.8°F).
What months are the sea warmest in Ascension Island?
March through May, with an average sea temperature of 28°C (82.4°F), are months with the warmest seawater in Ascension Island.
What is the month with the most sunshine in Ascension Island?
March and April, with an average of 8.9h of sunshine, are months with the most sunshine in Ascension Island, Saint Helena, Ascension and Tristan da Cunha.
What is the rainiest month in Ascension Island?
The month with the most rainfall is April, when the rain falls for 4 days and typically aggregates up to 33mm (1.3") of precipitation.
What is the month with the shortest days in Ascension Island?
The month with the shortest days in Ascension Island is June, with an average of 11h and 42min of daylight.
What is the month with the lowest UV index in Ascension Island?
The months with the lowest UV index in Ascension Island are June and July, with an average maximum UV index of 9.
What is the least humid month in Ascension Island?
The least humid month is July, with an average relative humidity of 67%.
What is the coldest month in Ascension Island?
The lowest level of Ascension Island's temperatures is noted during August through November, averaging a high-temperature of 28°C (82.4°F).
When is the sea coldest in Ascension Island?
September and October, with an average sea temperature of 24°C (75.2°F), are months with the coldest seawater in Ascension Island, Saint Helena, Ascension and Tristan da Cunha.
What is the month with the least sunshine in Ascension Island?
The month with the least sunshine in Ascension Island, Saint Helena, Ascension and Tristan da Cunha, is October, with an average of 5.2h of sunshine.
When are the longest days in Ascension Island?
December has the longest days of the year in Ascension Island, Saint Helena, Ascension and Tristan da Cunha, with an average of 12h and 36min of daylight.
Is there Daylight Saving Time (DST) in Ascension Island?
Ascension Island does not observe Daylight Saving Time (DST). GMT timezone is used throughout the entire year.
Average temperature
Ascension Island, Saint Helena, Ascension and Tristan da Cunha
The warmest months (with the highest average high temperature) are February, March, April and May (31°C).
The months with the lowest average high temperature are August, September, October and November (28°C).
The months with the highest average low temperature are March, April and May (24°C).
The coldest months (with the lowest average low temperature) are July, August, September, October, November and December (22°C).
Average humidity
Ascension Island, Saint Helena, Ascension and Tristan da Cunha
The month with the highest relative humidity is January (70%).
The month with the lowest relative humidity is July (67%).
Average rainfall
Ascension Island, Saint Helena, Ascension and Tristan da Cunha
The wettest month (with the highest rainfall) is April (33mm).
The driest months (with the least rainfall) are January, November and December (4mm).
Average rainfall days
Ascension Island, Saint Helena, Ascension and Tristan da Cunha
- Average rainfall days in January:
2 days - Average rainfall days in February:
2 days - Average rainfall days in March:
3 days - Average rainfall days in April:
4 days - Average rainfall days in May:
3 days - Average rainfall days in June:
3 days
- Average rainfall days in July:
3 days - Average rainfall days in August:
3 days - Average rainfall days in September:
2 days - Average rainfall days in October:
3 days - Average rainfall days in November:
1 days - Average rainfall days in December:
1 days
The month with the highest number of rainy days is April (4 days).
The months with the least rainy days are November and December (1 days).
Average sea temperature
Ascension Island, Saint Helena, Ascension and Tristan da Cunha
The best months for swimming (with the highest average sea temperature) are March, April and May (28°C).
The coldest months (with the lowest average sea temperature) are September and October (24°C).
Average daylight / Average sunshine
Ascension Island, Saint Helena, Ascension and Tristan da Cunha
- Average daylight in January:
12h and 3min - Average daylight in February:
12h and 2min - Average daylight in March:
12h and 1min - Average daylight in April:
11h and 5min - Average daylight in May:
11h and 5min - Average daylight in June:
11h and 4min
- Average daylight in July:
11h and 4min - Average daylight in August:
11h and 5min - Average daylight in September:
12h and 1min - Average daylight in October:
12h and 2min - Average daylight in November:
12h and 3min - Average daylight in December:
12h and 4min
The month with the longest days is December (Average daylight: 12h and 36min).
The month with the shortest days is June (Average daylight: 11h and 42min).
- Average sunshine in January:
7h and 2min - Average sunshine in February:
7h and 5min - Average sunshine in March:
8h and 5min - Average sunshine in April:
8h and 5min - Average sunshine in May:
8h and 3min - Average sunshine in June:
8h and 4min
- Average sunshine in July:
7h and 4min - Average sunshine in August:
7h and 0min - Average sunshine in September:
5h and 3min - Average sunshine in October:
5h and 1min - Average sunshine in November:
5h and 2min - Average sunshine in December:
6h and 2min
The months with the most sunshine are March and April (Average sunshine: 8h and 54min).
The month with the least sunshine is October (Average sunshine: 5h and 12min).
Average UV index
Ascension Island, Saint Helena, Ascension and Tristan da Cunha
The months with the highest UV index are January, February, March, April, September, October, November and December (UV index 12).
The months with the lowest UV index are June and July (UV index 9).
Ascension Island, Saint Helena, Ascension and Tristan da Cunha
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