And Christmas is the point at which this all comes together in a big way for the residents of the UK, something that they can not only talk about but also bet on – whether or not it will be a white Christmas. It is down to the Met Office to confirm if we have a white Christmas – and the official definition may surprise you;
For many people, a White Christmas means a complete covering of snow falling between midnight and midday on 25 December.
However, the definition used most widely, notably by those placing and taking bets, is for a single snowflake (perhaps among a mixed shower of rain and snow) to be observed falling in the 24 hours of 25 December at a specified location.
White Christmases were more frequent in the 18th and 19th centuries, even more so before the change of calendar in 1752 which effectively brought Christmas day back by 12 days. Climate change has also brought higher average temperatures over land and sea and this generally reduces the chances of a white Christmas. However, the natural variability of the weather will not stop cold, snowy winters happening in the future.
The graphic to the right from the Met Office indicates the amount of snow over the last few years on Christmas day – and it will not surprise anyone that it has increased in recent years – the question has to be why – but that’s for another day…..
White Christmas brings to mind two things – a great film (the best Christmas film ever in my opinion), and Christmas card pictures created by the weather. Everyone hopes for a ‘proper’ white Christmas, but if you can’t go to the mountains of Europe to find it, what are the chances at home?
Interestingly a lot depends on just how you classify a ‘white’ Christmas. The judge in all things white in the UK at Christmas is the Met Office, so how do they decide?
They classify ‘snow at Christmas’ as a single snowflake falling on the Met Office headquarters in Exeter or on the roof of the BBC in London over the 24 hours that make up the 25th December. It is this ‘official’ record that people normally bet on either happening or not. And surprisingly it is more common than you might expect. This criteria has been met 38 times in the last 51 years! That is an almost 75% success rate.
However, if we are talking lying snow on the ground at Christmas, this is actually much less common than you might think. Obviously we had this last year – but this was only the fourth time in 51 years!
Certainly the forecast for Christmas as it stands at the moment is not likely to give us a 5th one this year!