Last updated: January 18, 2025
Saint Helena, part of the remote South Atlantic archipelago of Saint Helena, Ascension, and Tristan da Cunha, experiences a BWh (arid) climate characterized by relatively mild temperatures throughout the year. With a minimum temperature of 18°C (64°F) recorded in October, the island enjoys an average temperature of 22°C (71°F), peaking at approximately 26°C (79°F) in February. This consistent warmth, combined with its unique geographic location, creates an intriguing environment that profoundly influences the island's ecological dynamics and human activities.
Saint Helena exhibits a mild temperature pattern throughout the year, characterized by warm summers and cooler winters. During the peak summer months of January and February, temperatures range from a minimum of 21°C (70°F) to a maximum of 26°C (79°F), creating an inviting climate. As autumn approaches in March and April, the temperatures remain stable, with averages around 24°C (75°F), before gradually declining into the cooler winter months of June, July, and August, where minimum temperatures drop to 18°C (64°F) and daytime highs reach only the low 20s°C. As spring returns in October and November, temperatures begin to rise again, reflecting a seasonal cycle that underscores the island's moderate climatic conditions.
In Longwood, Jamestown, and Half Tree Hollow, the temperatures are quite consistent throughout the year, with a minimum of 18°C (64°F) in October and a maximum of 26°C (79°F) in February. For more details, you can explore the monthly temperatures in Longwood, monthly temperatures in Jamestown, and monthly temperatures in Half Tree Hollow.
Saint Helena experiences relatively low precipitation levels throughout the year, with monthly rainfall averaging between 10 mm (0.4 in) and 16 mm (0.6 in). The months of January and February see the least amount of rain, with 10 mm and 12 mm, respectively, while March marks a slight increase with 16 mm. This pattern suggests a distinct drier season at the beginning of the year, gradually transitioning into slightly wetter months during late summer and early autumn, particularly in March and April when rainfall averages 16 mm and 14 mm, respectively.
Despite these rainfall totals, the number of rainy days remains minimal, with only a few days registering precipitation each month. January experiences no rainy days, while February has just one, escalating to three days in March and four in April. This trend exhibits an overall dry climate, with sporadic rain throughout the year, underscoring Saint Helena's reputation as a mostly arid environment despite the seasonal fluctuations in precipitation.
Saint Helena basks in an impressive amount of sunshine throughout the year, with a distinct seasonal trend that showcases longer days during the summer months. The peak sunshine occurs between March and April, where sunshine hours reach 324 and 305 hours, respectively, making these months excellent for outdoor activities and exploration. January and February also contribute significantly to the sun-drenched atmosphere with 277 hours and 313 hours, respectively. This impressive sunlight is indicative of the island's temperate climate, providing ample opportunity for residents and visitors to enjoy the stunning landscapes and natural beauty.
As the year progresses towards winter, however, sunshine hours begin to decline, with the lowest average recorded in June at 244 hours. The reduction continues into July and August, with totals of 272 and 248 hours, respectively, reflecting a period where overcast skies become more common. Despite this dip, sunshine hours rebound in the following months, particularly in November with 307 hours and a peak in December reaching 335 hours. This cyclical pattern emphasizes the contrasts between wet and dry seasons, illustrating how weather variables contribute not only to precipitation but also to the vibrant sunshine that characterizes Saint Helena.
Saint Helena experiences high levels of ultraviolet (UV) radiation throughout the year, particularly during the summer months when the UV Index reaches extreme levels. Both January and February report a notable UV Index of 15, requiring minimal sun exposure, with a burn time of just 10 minutes. As March and April approach, the index slightly decreases to 13 and 12, respectively, yet remains categorized as extreme. This consistent exposure calls for diligent sun protection measures during these peak months to mitigate the risks associated with intense UV radiation.
As the island transitions into winter, the UV Index begins to lessen but still maintains very high levels. For instance, while May and June exhibit indices of 9 and 8, requiring 15 minutes for potential skin burn, August sees a slight uptick to 10 before rising again to 11 in September. October and November return to extreme levels at 14, while December reverts to the peak of 15. These fluctuations underline the importance of year-round sun protection in Saint Helena, particularly during the summer months, where extreme care is essential to avoid skin damage from the sun's powerful rays.
UV Risk Categories
In Saint Helena, daylight duration presents a relatively stable pattern throughout the year, with variations that correspond to seasonal changes. From January to March, the island enjoys approximately 12 hours of daylight each day, allowing for ample time for outdoor activities and exploration. As spring approaches in April and continues through the winter months, daylight slightly decreases to 11 hours from April to August, reflecting the subtropical characteristics inherent in the region’s climate. This moderate drop signifies the transition into the cooler months while still offering plenty of daylight for residents and visitors to appreciate the island's natural beauty.
As the year progresses towards the end of the year, daylight duration begins to increase again. September, October, and November each return to 12 hours of daylight, heralding a return to longer days as the island shifts away from winter. By December, the daylight extends to 13 hours, providing the longest daylight period of the year. This seasonal fluctuation not only enhances the enchanting experience of visiting Saint Helena but also signals the island's unique position within the Atlantic, where daylight hours play a significant role in influencing local activities and lifestyle year-round.
The climate in Half Tree Hollow, Saint Helena, is characterized by mild temperatures year-round, with averages ranging from 19°C (66°F) in October to 24°C (75°F) in March and April. The region experiences relatively low precipitation, averaging between 10 to 16 mm monthly, with the wettest months being March and April. Sunshine is abundant, particularly from January to March, where it averages over 300 hours per month. Overall, Half Tree Hollow enjoys a comfortable, temperate climate suitable for outdoor activities throughout the year. For more details, visit Half Tree Hollow climate.
Jamestown, located on Saint Helena, experiences a mild maritime climate characterized by warm temperatures and moderate precipitation throughout the year. Average temperatures range from a minimum of 18°C (66°F) in August to a maximum of 26°C (79°F) in February, with minimal variation between seasons. Monthly rainfall is relatively low, peaking at 16 mm (0.6 in) in March and dropping to 10 mm (0.4 in) during the drier months. The island enjoys substantial sunshine, especially in March and December, with over 300 hours of sunshine recorded in those months. For more detailed information, see Jamestown climate.
The climate in Longwood, Saint Helena, is characterized by mild temperatures and moderate precipitation throughout the year. Average temperatures range from 18°C (64°F) in the cooler months of October and August, to a warm 24°C (75°F) in March and April. Rainfall is relatively light, with monthly averages peaking at 16 mm (0.6 in) in March, while sunshine is abundant, especially in February and December, with over 300 hours of sunlight. Overall, Longwood offers a pleasant climate ideal for outdoor activities. For more information, visit the Longwood climate.
In conclusion, Saint Helena, with its distinctive climatic patterns, offers a unique blend of mild temperatures, varying precipitation, and an abundance of sunshine. The island's arid BWh climate facilitates warm, sun-filled days, particularly from late summer to early autumn, while the UV Index highlights the need for sun protection during peak exposure periods. The steady daylight duration, characterized by around 12 hours per day for much of the year, allows for ample opportunities to explore its natural and cultural offerings. Collectively, these climatic elements underscore the charm and allure of Saint Helena, making it a captivating destination rich in both ecological diversity and historical significance.