Although the Scandinavian country escaped a heatwave that hit Europe in May, above average temperatures in March and April contributed to the record, said a weather institute statement.

"The sun is too stable to explain today's rapid climate change. It must be caused by our emissions of fossil fuels," climatologist Jostein Mamen stressed.

The previous warmest spring was recorded in 2024, when temperatures were 1.8C above normal, with 2025 the second warmest.

The warming was particularly noticeable in northern Norway.

In Svalbard, an archipelago halfway between mainland Norway and the North Pole, temperatures in April were sometimes 5 to 6 degrees above normal, according to the institute.

The Arctic warms much faster than other regions due to a process known as Arctic amplification.

This is caused by several factors, including when the sea ice and snow, which naturally reflect heat, melt into sea water, which absorbs it instead.

According to the UN, global average temperatures are expected to remain "at or near record levels" for the next five years.

Global rising temperatures lead to an increased risk of heat stress, drought in some regions, and extreme weather events such as flooding or severe droughts.