Climate zone: The northern part of Saint Helena, Ascension and Tristan da Cunha is located in the equatorial tropics, the southern parts of the country belong geographically to the subtropics.
Several months of the year it is warm to hot at temperatures continuously above 25 degrees centigrade, sometimes up to 28 degrees.
› Duration of daylight and sunshine in Saint Helena
hours of sunshine per day rainy days per month Precipitation in mm/day Relative humidity in % Absolute humidity in g/m³ (approx.)
Temperature records of the last 70 years
The hottest temperature measured from 1950 to August 2020 was reported by the Ascencion Island Airp weather station. In June 2014 the record temperature of 30.1 °C was reported here. The hottest summer from July to September, based on all 3 weather stations in Saint Helena below 440 metres altitude, was recorded in 1975 with an average temperature of 26.6 °C. This average temperature will normally be measured every 4 to 6 hours, thus also including the nights. Normally, this value is 22.4 degrees Celsius.
The coldest day in these 70 years was reported by the weather station Ascencion Island Airp. Here the temperature dropped to 20.2 °C in August 2014. Ascencion Island Airp lies at an altitude of 86 meters above sea level. The coldest winter (January to March) was in 1950 with an average temperature of 16.8 °C. In Saint Helena, it is usual to have about 8.7 degrees more at 25.5 °C for this three-month period.
Long-term development of temperatures from 1986 - 2019
In contrast to single record values, a long-term development cannot simply be brought about by all weather stations in the country. Both the number and the locations are constantly changing. A simply calculated average value would give a falsified result. If several measuring stations in particularly cold mountain or coastal regions are added in one year, the average would already decrease as a result of this alone. If a station fails during the summer or winter months, it does not provide any values and falsifies the average again. The subsequent long-term development was therefore reduced to only 1 measuring points in order to have actually comparable data over as long a period as possible.
In the years 1986 to 2019 there were only these 1 weather stations in the whole country, which reported continuous temperature values (St Helena). From these weather reports we have created a long-term development that shows the monthly average temperatures. The hottest month in this entire period was 2019 with 22.4 °C. 1992 was the coldest month with an average temperature of 15.1 °C.
The average annual temperature was about 18.7 °C in the years after 1986 and about 18.9 °C in the last years before 2019. So it has hardly changed at all in the past 34 years. This trend only applies to the selected 1 weather stations in Saint Helena. A considerably more comprehensive evaluation of the global warming
has been provided separately.
More detailed information on global warming with a view by continent can also be found on our topic page on climate change
. Data basis: German Weather Service, individual values averaged and supplemented by own elements.