"It is pretty stunning."
Polar researcher Jonathan Wille told the Washington Post, "This event is completely unprecedented and up-ended our expectations about the Antarctic climate system."
Researcher Stefano Di Battista wrote on Twitter, "Antarctic climatology has been rewritten."
He described the temperature surge as "impossible" and "unthinkable".
The freakish heat is believed to be a random weather event.
It has not been linked to climate change, according to meteorologist Matthew Lazzara and Dr Meier. But if the event is repeated, it would be a major concern and could be an indicator of climate change, they told NBC News.
The Arctic has warmed at about twice the rate as the entire globe over the past 30 years, which has been widely blamed on climate change.
The Intergovernmental Panel on Climate Change (IPCC) says the polar regions are being increasingly impacted by climate change, with sea ice thinning dramatically.
It is projected that Earth's surface temperature will rise 1.5C above pre-industrial levels, perhaps within a decade.
A 1.5C cap on global warming – the aspirational goal of the 2015 Paris climate accord – has been embraced as a target by most of the world's nations.
Current carbon-cutting commitments under the treaty, however, still puts the world on a catastrophic path towards 2.7C of warming by 2100.
The IPCC is set to report its next findings – mostly focused on mitigating climate change – on April 4.
