The climate of Saint Helena Island
The climate on Saint Helena Island
, located in the Saint Helena, Ascension and Tristan da Cunha
territory in the South Atlantic Ocean, is classified under the Köppen climate system as a predominately maritime subtropical climate. The island exhibits rather uniform weather throughout the year, tempered by the surrounding ocean.
The temperatures range moderately from a higher average of 23°C (73.4°F) down to a lower average of 14°C (57.2°F) throughout the year. However, temperatures can rise slightly in the early months of the year, peaking at 23°C (73.4°F) in March
and cooling off down to 17°C (62.6°F) in August
. These maritime influences also moderate sea surface temperatures, fluctuating between 22°C (71.6°F) to 25°C (77°F) over the year.
Rainfall on Saint Helena Island is well distributed throughout the year with the totals per month varying from 30mm (1.18") to 90mm (3.54"). The wettest months tend to occur in Autumn and Winter, peaking at 90mm (3.54") in March. Correspondingly, the number of rainfall days per month follows a similar pattern, with a maximum of 16 days around mid-year and a minimum of 12 days towards end and start of the respective years.
The UV index suggests a high level of solar radiation throughout the year, maintaining averages of 12 in the early months and moderating between 7 to 9 in the middle of the year. Besides, the island experiences substantial daylight ranging from 11.2 hours to 13.1 hours across the year, with less sunshine hours in the middle of the year compared to the beginning and end.
The best time to visit Saint Helena Island
Owing to mild temperatures and moderate rainfall, there is no particularly drastic barring time to visit Saint Helena Island
. However, for warm-weather travelers, the period from January
may be the most sought after, as these months manifest the warmest temperatures averaging between 22°C (71.6°F) to 23°C (73.4°F), with sea temperatures hovering between 23°C (73.4°F) to 25°C (77°F). Moreover, these months witness a highly comfortable range of daylight hours varying between 11.7 hours to 12.9 hours.
The worst time to visit Saint Helena Island
While each month could offer its unique charm to potential visitors, the months from May
may prove somewhat challenging. This period marks a slight drop in temperatures, with average highs ranging from 17°C (62.6°F) to 19°C (66.2°F). Correspondingly, sea temperatures also exhibit a decline to between 20°C (68°F) to 22°C (71.6°F), potentially deterring sea-based activities. Additionally, this period showcases increased rainfall days per month, peaking at 16 days in June
Spring weather in Saint Helena Island
Spring months, stretching from September
, usher in a period of weather transition on Saint Helena Island
. These months witness average high temperatures transition from 18°C (64.4°F) in September to 19°C (66.2°F) in November and average low temperatures following a stable pattern of 15°C (59°F). Rainfall follows a declining trend over this period, moving from 54mm (2.13") to 30mm (1.18"), with rainfall days per month around the norm of 13 to 14 days.
Summer weather in Saint Helena Island
During the summer season of December
, the island experiences temperature highs averaging at 22°C (71.6°F) to 23°C (73.4°F), with lows around 18°C (64.4°F) to 19°C (66.2°F). Rainfall remains relatively moderate at this time, averaging between 53mm (2.09") to 68mm (2.68"), alongside an average of 14 rainfall days per month. The sea temperature stays comfortably, peaking between 22°C (71.6°F) to 25°C (77°F) and daylights hours tend to be generous, in excess of 12 hours.
Autumn weather in Saint Helena Island
The autumn months commence from March
and extend to May
. This period presents a quite rainy atmosphere with rainfall increasing in magnitude from 90mm (3.54") to 71mm (2.8"), although followed by a high number of rainfall days per month, from 15 to 16 days on average. Meanwhile, temperatures start their downward trend from 23°C (73.4°F) to 21°C (69.8°F), with sea temperatures also lowering from 25°C (77°F) to 24°C (75.2°F).
Winter weather in Saint Helena Island
Winter months of June
usher in a cooler period with average high temperatures declining to between 17°C (62.6°F) to 19°C (66.2°F), while average low temperatures reach their annual lowest between 14°C (57.2°F) to 16°C (60.8°F). Notably, rainfall retains its high, trending from 87mm (3.43") to 68mm (2.68") monthly average. Sea temperatures during this period average at their lowest between 20°C (68°F) to 22°C (71.6°F), providing a cooler maritime environment. In line with reduced daylight hours between 11.2 to 11.6 hours which turns into reduced sunshine hours as well.
Weather in January
Weather shifts brought about by the new year usher in a warm start to January
in Saint Helena Island
, Ascension, and Tristan da Cunha. Beachgoers appreciate the warmer conditions and may witness dramatic but brief rainy spells. Weather in January »
Weather in February
retains the warm, wet climate established in January
, albeit with markedly increased rainfall. On most days, there is a balance between periods of brilliant sunshine and sudden downpours. February's warmer average temperatures present an ideal opportunity for sighting various bird species that are lured out by the local flora and fauna. Weather in February »
Weather in March
approaches, the warmth persists and reaches its peak, resulting in the highest average temperature for the year. Walking tours during daylight hours can be a pleasure, as the hours of sunshine increase during the month. Despite the tropical rainfall patterns, days without precipitation are quite common. Weather in March »
Weather in April
witnesses a slight retreat in temperature, inviting more comfortable weather conditions overall. The UV index drops by a marginal amount as well, making outdoor activities slightly less arduous. While rainfall persists, the probability of uninterrupted days of sunshine increases, allowing more opportunities for outdoor exploration. Weather in April »
Weather 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. Weather in May »
Weather in June
heralds the approach of winter on the island as temperatures continue to decrease. Interestingly, despite the cooler weather, both marine and on-land wildlife flourish during this month, with ample opportunities for spotting endemic fauna. Weather in June »
Weather in July
brings about the coldest average temperature for the year on the islands. However, the amount of rainfall is somewhat reduced from the previous months, offering occasional breaks from the persistent showers. On the positive side, despite the cool weather, the UV index begins to rebound, ensuring plenty of sunlight. Weather in July »
Weather in August
upholds the cool trend established by July
, with the weather remaining relatively stable. Although this may not be the sunniest of months, it offers an overall comfortable climate for both outdoor activities and indoor relaxation. Weather in August »
Weather in September
ushers in slightly warmer temperatures, signaling the transition from winter to spring. The slight increase in temperature is balanced by the reduction in rainfall and consistent daylight hours. An average sea temperature of about 21°C (69.8°F) and the UV index rising to 11 indicates a gradual return to sunnier days. Weather in September »
Weather in October
amplifies the warm shift begun in September
, making the weather entirely pleasant. The island registers fewer rainy days than in previous months, offering more hours of glorious sunshine. The gently warming sea and gradually increasing temperature leads to a proliferation of marine life, attracting enthusiasts from all corners. Weather in October »
Weather in November
, the island reaches a pivotal moment in its climatic pattern, with the weather moving steadily towards its summer disposition. A consistent sea temperature, coupled with diminishing rainfall, graces the island with idyllic days. Weather in November »
Weather in December
wraps up the weather cycle in Saint Helena Island
, Ascension and Tristan da Cunha, marking a return to hotter temperatures. The weather remains warm and balmy, making for perfect beach days. Sea temperatures rise further to 22°C (71.6°F), creating an inviting setting for water sports and swimming. Weather in December »