Temperatures in the Arctic Circle hit an all-time record on Saturday, reaching a scorching 38C (100F) in Verkhoyansk.
The record is yet to be verified, but it shown to have been 18C higher than the average maximum daily temperature in June.
Hot summer weather is common in the Arctic Circle, but recent months have seen abnormally high temperatures.
The Arctic Circle is believed to be warming twice as fast as the global average.
Verkhoyansk, home to about 1,300 people, sits just inside the Arctic Circle, in remote Siberia. It has an extreme climate with temperatures falling in January to an average maximum of -42C and then surging in June to 20C.
But a continuous heat wave this year in the Arctic Circle has worried meteorologists. In March, April and May, the Copernicus Climate Change service reported that the average temperature was around 10C above normal.
“Year-on-year temperature records are being broken around the world, but the Arctic is warming faster than anywhere else on Earth,” said Dr Dann Mitchell, associate professor in atmospheric science at the University of Bristol