A particularly cold and prolonged winter would surely suit Russian President Vladimir Putin, some analysts say, after Moscow drastically cut gas supplies to Europe in retaliation for Western support for kyiv.
In recent years, Western Europe has experienced a particularly harsh winter season in 2010/2011 as well as Siberian cold in 2018, which had killed several dozen people and caused major transport disruptions.
If this happens again, in the context of the scarcity of Russian gas, which represents a non-negligible part of the energy supply of certain European countries, it could cause significant difficulties with the possible consequence of blunting the determination of the EU. to support Ukraine.
"Energy is a one-shot weapon and it just fired," Eliot A. Cohen, a war historian and security expert at Johns University's Center for Strategic and International Studies, told AFP. Hopkins.
In an attempt to take the lead, many governments have called on households and businesses to turn down the heating and save energy, as part of a European plan to reduce gas consumption this winter by at least 15% by compared to the average of the last five years.
Forecasts in the viewfinder
The Twenty-Seven have also proceeded to the accelerated filling of their strategic reserves, even if it means having to pay a high price for gas to Algeria, Qatar, Norway or the United States.
With approximately 90% of the reserves filled, the EU now considers itself equipped to guarantee energy security to its citizens.
Especially since the weather conditions promise to be "normal", said AFP Alireza Nahvi, associate researcher at the firm specializing in energy Wood Mackenzie.
This security is no less precarious and a harsher winter than usual represents a sword of Damocles.
Faced with this challenge, many eyes - in industrial and political circles - are turned towards the European Center for Medium-Range Weather Forecasts (ECMWF).
Equipped with supercomputers capable of compiling data from the various national weather services, this organization is notably responsible for producing - via its Copernicus Service on Climate Change (C3S) - three-month rolling forecasts.
"This year, this issue is clearly of geopolitical interest," Carlo Buontempo, director of C3S, told AFP ahead of Thursday's release of forecasts for the November-January period.
Although it is still too early to make a perfectly reliable forecast, the first indications available point to a generally mild winter, with however a risk of early cold spells in November and December.
Wind direction
"It's the direction of the wind that matters. If, from mid-November to December, we have some of these strong winds coming from the east and snow over Europe, it will certainly have an impact on the gas demand, prices and geopolitics", explains Mr. Buontempo.
On the other hand, after a summer marked by record heat in Europe, the Atlantic Ocean is warmer than usual, and the phases of westerly winds could keep temperatures mild.
Under average temperatures and assuming a reduction in gas demand of around 9% this year, Europe will get by without major disruption, the International Energy Agency (IEA) recently calculated.
However, if "we have a winter about 10% colder than average, the European gas system will find itself under pressure", warns Gergely Molnar, gas analyst at the IEA.
A factor not to be overlooked will be the level of stocks, mainly held in depleted gas fields or aquifers.
These reserves may be about 90% full, but they are difficult to access, because as the stocks run out, the pressure decreases, making the last 30% difficult to extract.
A late cold spell, in February or March, when the pressure will be low, constitutes the “Achilles heel of the security of European gas supply”, warned the IEA.