It’s that time of year when people start imagining waking up to find that Santa has visited, with the streets blanketed by a crisp white layer of fresh snow covering the streets on Christmas Day.
But the Met Office, which says it starts being asked about whether it will be a white Christmas as early as October, has explained the difficulty in making accurate predictions and snowfall living up to people’s festive expectations.
Despite media reports about snow to come, the forecaster called for patience – explaining it is not until the final week before Christmas that it can accurately predict the chances of seeing any snow flurries on the big day.
Met Office meteorologist Aidan McGivern said: “What meteorologists actually do, is rather than cherry pick one computer model run for more than two weeks’ time, the computer models are run lots and lots of times and then we can pick out areas where they are agreeing and areas where they are disagreeing.
“Then we can talk about likely weather patterns and less-likely weather patterns, common themes and so on.”
The experts stressed the tricky nature of making such early predictions, explaining that just a fraction of a degree in temperature “can make the difference between the chance to build a beautifully formed snowman, and the joys of a sleety slushy day”.
To declare a white Christmas in the UK the forecaster simply needs one observer or an automatic station to report a single snowflake falling on 25 December.
Technically 2023 was the last white Christmas in the UK, with 11% of stations recording snow falling – but none reporting any actually settling on the ground.
Since 1960, around half of the years have seen at least 5% of the station network report snow falling on the big day, meaning more than half of all Christmas Days are technically a ‘white Christmas’.
But for it to settle is much rarer. There has been a widespread covering of snow on the ground – 40% of stations in the UK reporting snow settling at 9am on Christmas Day – only four times in 1981, 1995, 2009 and 2010.
The last widespread white Christmas in the UK was in 2010. It was extremely unusual, as not only was there snow on the ground at 83% of stations – the highest amount ever recorded – but snow or sleet also fell at 19% of stations.
So what will it be this year?
The Met Office’s current long-range forecast for Christmas week predicts spells of wind and rain, and “perhaps with some hill snow in the north”. Predictions should become more accurate closer to the date, so watch this space.
