Most of Antarctica is a high flat plateau of ice covered in snow. Antarctica is cold because it is high and because it is covered in snow year round. The white snow reflects the sun's solar radiation very efficiently. With the warming effect of the sun reduced, combined with the altitude, the coldest temperatures recorded in the world are in the interior of Antarctica. The lowest recorded temperature in the world was at Vostok Station and was -128.6°F (-89.2°C) recorded in July 1983. The lowest recorded temperature at South Pole, also recorded during the dark winter months, was -117.0°F (-82.8°C) on June 23, 1982. Even at the high of summer the maximum temperature recorded at the South Pole is still well below freezing at +7.5F (-13.6°C), recorded December 27, 1978.
The strong winds of Antarctica are called katabatics and are caused by the cold dense air of the polar plateau flowing out from the interior. The average alititude of Antarctica is 14,000 feet, with most of the verticle gradient near the coast of Antarctica. It is at the steep edge of Antarctica that the strong katabatic winds form as the cold air rushes down the steep slopes of the coast. The highest recorded winds in Antarctica were at Dumont d'Urville station in July 1972 at 199mph (327km/h). The strongest gust of wind recorded in the world was at Mount Washington, New Hampshire (USA) on 12 April 1934, at 199mph (327km/h).
The South Pole is well inland on the polar plateau at an altitude of 9300 feet. Because it is at altitude and in the middle of the white plateau the temperature remains very low. There is only one day and one night every year at the South Pole, with the sun setting on March 21, and rising on Spetember 21, each year. During the summer months the sun slowly spirals up to its maximum height, and then back down to the horizon again over a 6 month period, never setting. It is during the dark winter months that the South Pole is extremely cold. Because the South Pole is well inland and on a flat area of the plateau the katabatic winds are relatively mild, and the maximum recorded wind was only 48 knots.
| Highest Recorded Tempertaure | +7.5°F (-13.6°C) December 27, 1978 |
| Lowest Recorded Tempertaure | -117.0°F (-82.8°C) June 23, 1982 |
| Average Annual Temperature | -57.1°F (-49.5°C) |
| Peak Wind | 48 kts (55 mph) from 330 degrees on August 24, 1989 |
| Average Wind | 10.7 kts (12.3 mph) from 020 degrees |
| Maximum Pressure | 719.0 mbs on August 25, 1996 |
| Minimum Pressure | 641.7 mbs on July 25, 1985 |
| Average Pressure | 681.3 mbs |
Halos are a form of atmospheric optical phenomena, such as rainbows, except caused by ice crystals rather than rain drops. Halos are caused by external reflection and internal refraction of light through evenly shaped and oriented ice crystals in the atmosphere. Different halos are caused by 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 sun dogs (bight areas of light either side of the sun). Common halos such as the 22 degree halo and sundogs can been seen anywhere in the world and is most commonly seen in light cirrus cloud cover. Antarctica is a great place to see and study halos because of the unique atmospheric conditions. A number of halos have only been observed at the South Pole.