Europeans looking for a White Christmas are set to be disappointed as unseasonally warm air and wet weather are likely to characterise the festive season.

A wave of warm air carried by Storm Elsa which is pushing across the Atlantic from the Caribbean and Storm Fabian is spreading heat upwards from the Mediterranean sea and North Africa.

Temperatures are expected to reach as high as 16C in Palermo in Sicily on Christmas Day, but even the usually frosty St Petersburg is going to see temperatures as high as 5C, according to the BBC.

Historically, the former Russian capital was so cold during the winter its River Neva freezes over.

Meanwhile, Switzerland recorded its highest ever December temperature (20.5C) on Tuesday and there is not likely to be any snow at Christmas. In Geneva, the forecast is for 10C and rain.

Michael Krucker, a forecaster with Meteonews in Switzerland, said snow was unlikely anywhere in the country except for settlements above 1,000-metres altitude. The country normally has a 20-30% chance of a white Christmas.

He said milder Christmas periods were a sign of climate change.

“In future, it will be warmer at Christmas. They are only small changed but over a long time I would say we can see a clear pattern.”

Similarly, Steen Rasmussen, the chief forecaster at the Danish Meteorological Institute, said temperatures at Christmas would be "well above normal" for December.

"Denmark will have a mild week without snow," he explained.

In France, the air is expected to remain warm over the next days, with strong winds travelling through the country from the west, according to Meteo France.

Storm Fabien, which is expected to hit France's Atlantic coast between Saturday and Sunday, will carry strong winds of up to 130km/h and bring more warm air from the Mediterranean and northern Africa, Meteo France told Euronews.

Southern France is on alert for violent storms, high winds and floods.

"There will be snow in altitude, in mountains like the Alps, but not in the plains", a spokesperson for Meteo France said. "So there will be no white Christmas."

At least, not in France: "The weather will be far too mild for that."

But it is not all bad: skiers in the Alps have seen some of the largest snow dumps in recent years. Ski resorts on the French/Italian border reported up to 1.5 metres in early November, according to the MountainWatch snow blog.

Although the temperatures will remain mild in most places, many places will be overcast and rainy.

Many Europeans may be facing a Grey Christmas instead.