University of Wisconsin-Madison

Antarctic Weather

Cold

Most of Antarctica is a high, flat plateau of ice covered in snow throughout the year. The snow reflects the sun's solar radiation, and this combined with the altitude (an average of 14,000 feet above sea level) makes the interior of Antarctica the coldest place on Earth.

The lowest recorded Antarctic temperature was taken at Vostok Station in July 1983: -89.2°C (-128.6°F). The lowest South Pole temperature is from June 23, 1982: -82.8°C (-117.0°F). The warmest temperature ever recorded at the South Pole, recorded at the height of the austral summer, December 25, 2011, was still well below freezing: -12.3°C (+9.9°F).

An example of a sun pillar
An example of a sun pillar

Wind

The strong winds of Antarctica are called katabatics, formed by cold, dense air flowing out from the polar plateau of the interior down the steep vertical drops along the coast. It is at the steep edge of Antarctica that the strong katabatic winds form as cold air rushes.

The highest wind speeds recorded in Antarctica were at Dumont d'Urville station in July 1972: 327km/h (199 mph), equal to the strongest wind gust recorded in the world at Mount Washington, New Hampshire (USA) on April 12, 1934, at 199mph (327km/h). Because the South Pole is well inland and on a flat area of the plateau, the katabatic winds are relatively mild. The highest recorded wind at the South Pole was only 48 knots (55 mph).

South Pole

The South Pole is well inland on Antartica’s polar plateau at an altitude of 9,300 feet. Because of the altitude and its location in the middle of the white plateau, the temperature remains very low. There is only one sunrise and one sunset each year at the South Pole: the sun rises on September 21 and sets on March 21. During the summer months the sun slowly spirals up to its maximum height and then back down to the horizon again over a six month period, never setting until March 21, when the sun then remains below the horizon for the next six months. It is during the dark winter months that the South Pole is extremely cold.

Highest Recorded Temperature +9.9°F (-12.3°C) December 25, 2011
Lowest Recorded Temperature-117.0°F (-82.8°C) June 23, 1982
Average Annual Temperature-57.1°F (-49.5°C)
Peak Wind48 kts (55 mph) from 330 degrees on August 24, 1989
Average Wind10.7 kts (12.3 mph) from 020 degrees
Maximum Pressure719.0 mbs on August 25, 1996
Minimum Pressure641.7 mbs on July 25, 1985
Average Pressure681.3 mbs

Halos

Halos are optical phenomena caused by external reflection and internal refraction of light through evenly shaped and oriented ice crystals in the atmosphere. Variations in halos are caused by different combinations of ice crystal shapes and orientations, as well as different combinations of reflections and refraction within the crystals. The most common halos are the 22-degree halo (a circle around the sun or moon) and parhelion, also known as sundogs, (bight areas of light either side of the sun). Though these more common halos can be seen elsewhere in the world, the unique atmospheric conditions in Antarctica make it an especially great place to see and study halos; there are a number of halo types that have only been observed at the South Pole.

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Bibliography/References