Temperatures around the North Pole surged close to melting point on Thursday as a freak blast of warm air blanketed an Arctic region usually deep frozen in mid-winter darkness, scientists said.

Air temperatures at the North Pole were an estimated minus 4 degrees Celsius (24.8 Fahrenheit) around midday with light snow, according to the Norwegian Meteorological Institute, against a more usual temperature close to minus 30 degrees Celsius (minus 22 Fahrenheit).

There are no weather stations at the Pole itself but a buoy floating in the Arctic Ocean north of the Norwegian island of Spitsbergen was reporting zero degrees C on Thursday.