An exceptionally early stratospheric warming of the polar vortex is being anticipated from the beginning of November, with a risk of cold air descending over Europe in the following weeks. But will Lyon really be affected? We explain.
An exceptional meteorological phenomenon expected in early November
It's a situation that's particularly catching meteorologists' attention. According to La Chaîne Météo, the latest simulations from the European ECMWF model indicate a significant risk of sudden stratospheric warming, also called SSW, at the beginning of November 2026. A phenomenon that's nothing unusual in the middle of winter, but which becomes much rarer at this time of year. Usually, these disturbances occur mainly in January or February. This time, they could appear as early as the first days of November. According to Severe Weather Europe's analysis, the polar vortex could begin to weaken between October 31st and November 6th. A particularly early development, wh
could have consequences on the weather in the following weeks.But what exactly is a polar vortex?
Behind this name that sounds straight out of a disaster movie lies a very real atmospheric phenomenon. The polar vortex is a vast circulation of extremely powerful winds that rotates around the Arctic, at several tens of kilometers altitude. When it's stable, it helps keep the coldest air masses in polar regions. But when this circulation is heavily disrupted, particularly by a sudden warming of the stratosphere, it can weaken or become distorted. The result: atmospheric conditions can become more favorable for cold air masses to descend toward certain regions of Europe or North America. Be careful though: a disrupted polar vortex doesn't automatically mean a cold snap in France.
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Could Lyon experience a cold snap as early as November?
That's definitely the question we're all wondering about! According to La Chaîne Météo, this weather system could favor polar air masses moving toward Europe during the second half of November and the beginning of December. France could therefore experience colder spells than usual for the season. But at this stage, it's impossible to say whether Lyon or the Auvergne-Rhône-Alpes region will be directly affected. The intensity of the cold, its duration, and which regions will be impacted remain highly uncertain. And contrary to what you might think, this phenomenon doesn't necessarily mean the arrival of freezing temperatures or heavy snowfall in the City of Light. Everything will depend on how atmospheric conditions evolve over the coming weeks.
Such an early phenomenon is extremely rare!
What intrigues specialists most is the timing of this weather system
could occur. According to Weather Channel, sudden stratospheric warmings occur regularly during winter, but rarely this early. The previous record for early occurrence dates back to November 28, 1968, a date also reached in 2025. An event as early as the beginning of November would therefore be a particularly unusual situation. That said, meteorologists remind us that a winter that is globally milder than normal can perfectly well experience a few episodes of intense cold.Should we already dig out our winter coats in Lyon?
No need to panic—forecasts don't yet allow us to announce an exceptional cold wave in Lyon. The coming days will be crucial for observing the evolution of the polar vortex and its potential consequences on European weather. One thing is certain: the second half of November will be closely monitored by meteorologists.