Britain braced for freezing temperatures as Met Office warns weakened polar vortex could bring snow

The UK could soon be plunged into freezing temperatures due to a disruption of winds high in the atmosphere by El Niño. The weather phenomenon is currently disrupting a circle of winds spinning high in the atmosphere, known as the stratospheric polar vortex. Although it forms far above the UK, the strength and shape of the polar vortex can affect the behaviour of the jet stream. A strong polar vortex supports a strong, straight jet stream across the North Atlantic - creating milder, wetter and windier conditions in the UK.

However, a weaker vortex can lead to freezing air being pushed south from the Arctic towards North America and Europe . Read more: Remnants of US Hurricane sweep through UK as Super El Niño breaks records Read more: Met Office releases first winter outlook as weakening 'Polar Vortex' could see UK plagued by freezing temperatures “A highly unusual disruption of the stratospheric polar vortex is now underway,” a spokesperson for the Met Office said.

“If it becomes a major Sudden Stratospheric Warming (SSW), it will be the earliest such event on record.” The El Niño weather phenomenon may be contributing to the disruption, as it is associated with an increased likelihood of sudden stratospheric warmings. El Niño occurs when sea-surface temperatures in parts of the tropical Pacific become warmer than average and can affect weather patterns in Europe. Historically, El Niño events have tended to be associated with warmer, wetter and stormier conditions across the UK and northern Europe during late autumn and early winter.

A major SSW does not automatically mean snow or severe cold for the UK, although it does increase the chances of colder weather. For example, in November 2025 there was a SSW, but it did not lead to significantlly colder weather for the UK. The outcome depends on how the lower atmosphere responds, including where areas of high pressure form, weather patterns over the North Atlantic and Europe, and the behaviour of the jet stream. The long-range forecast suggests below-average temperatures for the rest of November, before rising to slightly above average at the end of the month.

Although it says there will be "unsettled or changeable" weather, the Met Office does not say temperatures will be freezing. In a recent blog update, the Met Office said: "When an SSW affects conditions near the surface, it can weaken the jet stream and encourage blocking high pressure over the North Atlantic, Greenland, or Scandinavia, disrupting Atlantic weather systems and changing the air reaching the UK. "If high pressure becomes established to the north or northeast of the UK, colder easterly winds can impinge on the UK.

These tend to bring colder, drier air and can produce sleet or snow showers, especially in eastern areas. "In other setups, northerly winds can bring cold Arctic air southwards, increasing the risk of wintry showers, ice or snow, depending on temperatures and moisture." Met Office presenter and meteorologist Aidan McGivern added: “El Niño is basically enhancing the waves that go on in the troposphere, the wriggly jet stream. Those waves can then propagate upwards into the stratosphere, knocking, bumping and disturbing that circle of winds around the polar stratosphere, causing it to be displaced, pushed off the pole, deformed or even split.”

It is a good example of a “teleconnection”, the Met Office adds, where atmospheric changes in one part of the world influence weather patterns thousands of kilometres away. The current disturbance is already producing warming in the stratosphere above the North Pole. Forecast show temperatures continuing to rise, while the normally westerly winds surrounding the vortex weaken. If it does happen, its timing would be particularly unusual, the forecaster said, adding: "It would be exceptionally early in the season compared with the events meteorologists are more accustomed to analysing later in winter."

Mr McGivern added: “We know that El Niños increase the chances, through this chain of events, of sudden stratospheric warmings happening, and we know sudden stratospheric warmings increase the chance of colder weather for the UK. So we’ve got this chain of events that we can start to flag well in advance.”