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Live forecasts update automatically; written guidance last reviewed 16 June 2026 by the WordPatch weather desk. Data from national met services via Open-Meteo.
Sudden stratospheric warming (SSW) is a rapid rise in temperature high above the North Pole, often by 50°C in a few days, which can weaken or reverse the polar vortex. For the UK, this disruption increases the chance of cold, blocked weather patterns and easterly winds, sometimes bringing widespread snow and freezing temperatures weeks later.
What causes sudden stratospheric warming, and when does it happen?
SSW occurs when large atmospheric waves, generated by mountain ranges and weather systems, travel up into the stratosphere and break, dumping their energy. This slows or reverses the usual westerly polar vortex winds. Events are most common between November and March, with notable occurrences in early 2025 and forecast models tracking potential events for 2026. The Met Office monitors these developments closely to assess the risk of blizzards for the UK.
What are the consequences of sudden stratospheric warming for UK travellers?
The main consequence is a heightened chance of disruptive cold weather, including snow and ice, often lasting 2–4 weeks. If you are travelling in late winter or early spring, check the 10-day forecast regularly and consider packing extra layers. School holidays can be affected if road or rail services struggle. For a full list of UK weather updates, keep an eye on official warnings.
Can sudden stratospheric warming be predicted?
Yes, forecast models can spot a likely SSW event 1–2 weeks in advance. The Met Office issues alerts once confidence is high, but the exact timing and local UK impacts remain uncertain until closer to the event.
Does sudden stratospheric warming always bring snow to the UK?
No. While an SSW increases the odds of cold, blocked weather, the exact outcome depends on the position of high pressure. Some events bring dry, crisp conditions rather than heavy snow.
What is the latest on sudden stratospheric warming for 2025–2026?
Forecasters are watching for potential SSW development in early 2026. As of late 2025, no major event is confirmed, but seasonal models suggest an increased risk of a cold snap in late winter.