Climate in South Orkney Islands (Antarctica)

The South Orkney Islands have a polar climate, with average temperatures around -8/-9 °C (16/18 °F) in winter, from June to August, and 0.5/1.5 °C (33/35 °F) in summer, from December to March.
The islands are located in the South Atlantic Ocean, north-east of the Antarctic Peninsula and south-east of Tierra del Fuego, at a latitude of 60 degrees south (the same, on the other side of the world, as Oslo, the capital of Norway).



The archipelago is made up of four main islands: Coronation (the largest), Laurie (the easternmost, where the Argentine Orcadas base is located), Powell, and Signy (where a British research station is located). Inside the islands there are elevations. The highest peak is Mount Nivea, 1,266 meters (4,153 feet) high, located on Coronation Island.
The climate of the South Orkneys is influenced by the westerly winds, which blow regularly around Antarctica (in this area, from the north-west), often with storm intensity, and bring relatively mild but also cloudy and windy weather, with frequent snowfall, and sometimes rain. However, Antarctic winds can also arrive, bringing cold and dry weather, with better visibility. The alternation of these two meteorological situations means that there is considerable variability in the climate of these islands, especially in winter, when the wind can bring ice drifting from the Weddell Sea, causing the temperature to drop by tens of degrees.

Temperatures are lower than one would expect from the latitude, due to the Weddell Sea Current, which transports cold waters from Antarctica, and as we said can bring icebergs, especially from April to November.
During cold waves, the temperature can drop to -32/-33 °C (-26/-27 °F) from June to September, although in the last century it has sometimes fallen to lower values. In 1972, at the Orcadas base, the temperature reached -39 °C (-38 °F) at the end of June, and according to some sources it even reached -44 °C (-47 °F) in August. The first value is generally accepted, while the second is doubtful, although it cannot be excluded, given that in that winter, there was an anomalous drift of ice from the Weddell Sea towards the north.
On the other hand, when mild currents prevail, temperatures can exceed freezing even in winter, while in summer they can reach 10 °C (50 °F), and occasionally 12/13 °C (54/55 °F). With mild currents from the north, the warmest areas are the southern coast of Coronation Island, which receives föhn-like, downslope winds from the mountains, and the smaller island of Signy, which lies just south of the former. In January 1982, the temperature at Signy Station reached 19.8 °C (67.6 °F), which is the record for all regions around Antarctica south of the 60th parallel.
Here are the average temperatures recorded in the aforementioned Orcadas base, located on Laurie Island, founded in 1903 by a Scottish expedition and then transferred to the Argentine government.

Precipitation is frequent, although not abundant, as it amounts to 660 millimeters (26 in) per year. Tt typically occurs in the form of snow or sleet, but sometimes it can also rain. On average, there are 222 days with snow per year, with a minimum of 13 days in February and a maximum of 21.5 days in October.
There is also a high number of days with fog or mist.
Here is the average precipitation.

There is very little sunshine in South Orkney. Cloudy or overcast days are normal all year round. Days with clear skies are very rare. With just over 400 hours of sunshine a year, the South Orkney Islands are the least sunny place in the world.
Here are the average sunshine hours per day.

The wind blows frequently. The average is 25 kph (15.5 mph) at the Signy station and 22 kph (13.5 mph) at Orcadas base. In the latter, the average over the year ranges from 20 kph (12.5 mph) in December and January, to around 25 kph (15.5 mph) in the other months. Days with strong winds are also frequent.