Extreme winter weather isn’t down to a wavier jet stream

The recent erratic behaviour of the polar jet stream isn’t out of the ordinary, researchers have found by compiling data from the past 125 years

By Madeleine Cuff

26 June 2025

A wavy polar jet stream can bring icy storms further south

Science History Images / Alamy Stock Photo

Increasingly erratic winter weather in the northern hemisphere isn’t a result of the polar jet stream getting more wavy, according to new research – although climate change is making winter storms more intense in other ways.

The northern polar jet stream is a current of winds that sweeps through the northern hemisphere, steered by the boundaries between temperate air and cold air around the Arctic.

Read more

Is a broken jet stream causing extreme weather that lasts longer?

Advertisement

For more than a decade, some researchers have suspected that a warming Arctic is causing the jet stream to buckle more dramatically in the winter, causing extreme storms that bring snow and ice much further south than usual.

But the theory has been hard to verify, in part due to the relatively short satellite data record, and also because of the jet stream’s intense natural variability during the winter months.

Erich Osterberg at Dartmouth College, New Hampshire, and his colleagues set out to identify whether the recent behaviour of the jet stream is out of the ordinary compared with the long-term average.