An Argentine research base near the northern tip of the Antarctic peninsula has set a heat record at a balmy 17.5 degrees, the UN weather agency has said.
The Experanza base set the high on March 24, 2015, the World Meteorological Organization (WMO) said on Wednesday after reviewing data around Antarctica to set benchmarks to help track future global warming and natural variations.
"Verification of maximum and minimum temperatures help us to build up a picture of the weather and climate in one of Earth's final frontiers," said Michael Sparrow, a polar expert with the WMO co-sponsored World Climate Research Programme.
Antarctica locks up 90 per cent of the world's fresh water as ice and would raise sea levels by about 60 metres if it were all to melt, meaning scientists are concerned to know even about extremes around the fringes.
The heat record for the broader Antarctic region, defined as anywhere south of 60 degrees latitude, was 19.8 degrees on January 30, 1982 on Signy Island in the South Atlantic, it said.
And the warmest temperature recorded on the Antarctic plateau, above 2500m, was -7 on December 28, 1980, it said.
Wednesday's WMO report only examined the highs.
The lowest temperature set anywhere on the planet was a numbing -89.2 at the Soviet Union's Vostok station in central Antarctica on July 21, 1983.
