Scientists confirm Antarctica's hottest recorded temperature

Scientists have confirmed the hottest-ever temperature recorded in Antarctica – 18.3C – which was captured in one of the fastest-warming regions of the planet.

The record reading, evaluated by a 12-person international team including Victoria University climate scientist Professor James Renwick, was announced by the World Meteorological Organisation (WMO).

The temperature was recorded at Argentina's Esperanza station on the Antarctic Peninsula – the continent's northwest tip near to South America - on February 6 last year.

That reading, which was around the average of a typical Auckland day in March, was also where the previous record, 17.5C, was observed in March 2015.

The record for the Antarctic region as a whole, including all ice and land south of 60° latitude, was 19.8C, taken at the UK's Signy Island station in January 1982.

WMO secretary-general Professor Petteri Taalas said the verification of the new record was important because it helped build up a picture of the weather and climate in one of Earth's final frontiers.

"Even more so than the Arctic, the Antarctic is poorly covered in terms of continuous and sustained weather and climate observations and forecasts, even though both play an important role in driving climate and ocean patterns and in sea level rise," Taalas said.

"The Antarctic Peninsula is among the fastest-warming regions of the planet, almost 3C over the last 50 years.

"This new temperature record is therefore consistent with the climate change we are observing."

Renwick was part of a team commissioned with reviewing the weather situation on the peninsula at the time the record – and another of 20.75C at nearby Seymour Island, but which was ultimately rejected – were taken.

The team determined that a large high-pressure system over the area created what are called föhn conditions – or downslope winds producing significant surface warming - which resulted in local warming at both the Esperanza and Seymour Island stations.

Past evaluations have demonstrated that such meteorological conditions were conducive for producing record temperature scenarios.

The new record will now be added to the WMO's Archive of Weather and Climate Extremes, which, among other figures, included the world's highest and lowest temperatures – 56.7C at California's Furnace Creek on July 10, 1913, and -89.2C at Vostok, Antarctica, on July 21, 1983.

Renwick said föhn conditions also caused New Zealand's highest recorded temperatures.

"The hottest day ever recorded in Aotearoa is still 42C in Rangiora and Christchurch, and other places in Canterbury, on February 7, 1973," he said.

"That happened in a big nor'westerly event just like the one that caused the new record for the Antarctic.

"The Antarctic Peninsula has mountains running down its length, perpendicular to the flow of the north-west winds, so places on the eastern side of the peninsula can experience very warm days, just like in Canterbury, which lies downwind of the Southern Alps."