Climate of Antarctica

The climate of Antarctica is the coldest on Earth. The lowest air temperature record on Antarctica was set on 21 July 1983, when −89.2 °C (−128.6 °F) was observed at Vostok Station. Satellite measurements have identified even lower ground temperatures, with −93.2 °C (−135.8 °F) having been observed at the cloud-free East Antarctic Plateau on 10 August 2010. The continent is also extremely dry (it is technically a desert), averaging 166 mm (6.5 in) of precipitation per year. Snow rarely melts on most parts of the continent, and, after being compressed, becomes the glacier ice that makes up the ice sheet. Weather fronts rarely penetrate far into the continent, because of the katabatic winds. Most of Antarctica has an ice-cap climate (Köppen classification EF) with very cold, generally extremely dry weather. The lowest reliably measured temperature of a continuously occupied station on Earth of −89.2 °C (−128.6 °F) was on 21 July 1983 at Vostok Station. For comparison, this is 10.7 °C (19.3 °F) colder than subliming dry ice (at sea level pressure). The altitude of the location is 3,488 meters (11,444 feet). The lowest recorded temperature of any location on Earth's surface at 81°48′S 63°30′E / 81.8°S 63.5°E / -81.8; 63.5 was revised with new data in 2018 in nearly 100 locations, ranging from −93.2 °C (−135.8 °F) to −98 °C (−144.4 °F). This unnamed part of the Antarctic plateau, between Dome A and Dome F, was measured on August 10, 2010, and the temperature was deduced from radiance measured by the Landsat 8 and other satellites, and discovered during a National Snow and Ice Data Center review of stored data in December, 2013 but revise by researcher on June 25 2018. This temperature is not directly comparable to the –89.2 °C reading quoted above, since it is a skin temperature deduced from satellite-measured upwelling radiance, rather than a thermometer-measured temperature of the air 1.5 m (4.9 ft) above the ground surface. The highest temperature ever recorded on the Antarctic continent was 17.5 °C (63.5 °F) at Esperanza Base, on the Antarctic Peninsula, on 24 March 2015. A higher temperature of 19.8 °C (67.6 °F) at Signy Research Station on 30 January 1982 is the record for the Antarctic region encompassing all land and ice south of 60° S. The mean annual temperature of the interior is −57 °C (−70.6 °F). The coast is warmer; on the coast Antarctic average temperatures are around −10 °C (14.0 °F) (in the warmest parts of Antarctica) and in the elevated inland they average about −55 °C (−67.0 °F) in Vostok.Monthly means at McMurdo Station range from −26 °C (−14.8 °F) in August to −3 °C (26.6 °F) in January.At the South Pole, the highest temperature ever recorded was −12.3 °C (9.9 °F) on 25 December 2011. Along the Antarctic Peninsula, temperatures as high as 15 °C (59 °F) have been recorded, though the summer temperature is below 0 °C (32 °F) most of the time. Severe low temperatures vary with latitude, elevation, and distance from the ocean. East Antarctica is colder than West Antarctica because of its higher elevation. The Antarctic Peninsula has the most moderate climate. Higher temperatures occur in January along the coast and average slightly below freezing. The total precipitation on Antarctica, averaged over the entire continent, is about 166 millimetres (6.5 inches) per year (Vaughan et al., J Climate, 1999). The actual rates vary widely, from high values over the Peninsula (15 to 25 inches a year) to very low values (as little as 50 millimetres (2.0 inches) in the high interior (Bromwich, Reviews of Geophysics, 1988). Areas that receive less than 250 millimetres (9.8 inches) of precipitation per year are classified as deserts. Almost all Antarctic precipitation falls as snow. Rainfall is rare and mainly occurs during the summer in coastal areas and surrounding islands. Note that the quoted precipitation is a measure of its equivalence to water, rather than being the actual depth of snow. The air in Antarctica is also very dry. The low temperatures result in a very low absolute humidity, which means that dry skin and cracked lips are a continual problem for scientists and expeditioners working in the continent. The weather in Antarctica can be highly variable, and the weather conditions can often change dramatically in short periods of time. There are various classifications for describing weather conditions in Antarctica; restrictions given to workers during the different conditions vary by station and nation.