The island is subject to a temperate oceanlike climate.

The average annual temperature of the air is 13.8°C with a short range extending from 11.2°C in August to 17.0° C in February. The extreme temperatures ever recorded under cover at sea-level are +1.8°C (July 1964) and 25.8°C (January 1989).

Rainfall (1121mm per year) mainly consists of drizzles. There is an average of 238 rainy days a year, winter being moister than summer. Howevever the heaviest rainfalls within 24 hours are recorded in summer when extratropical depressions and cyclone-tails sweep across the isle. The average annual humidity-rate of the air is 80% and without any seasonal variations.

North-westerly winds prevail and match the northernmost strong gales of the Roaring Forties. The average windspeed in a year at sea-level is 7.4 metres per second (m/s) (27 km/h). Violent gales (over 16 m/s) have usually been registered for 163 days a year with a peak of 56 m/s (200 km/h) in June 1950. The most violent winds ever registered on the base reached 140 km/h during the extratropical storm "Anacelle" on February 14th 1998.