I'm dreaming of a white Christmas... just like the ones I used to know
Dreaming Bing Crosby might be, but most long-term Londoners have wised up to the weather now. Despite Christmas cards depicting a white-washed capital, the reality is usually a bit more... grey. Read on to find out what the chances are of a snowy holiday season this year.
Does it snow in London at Christmas?
In a nutshell, not often, and not heavily. Given that London's already running on an urban microclimate that makes it warmer than the surrounding countryside, snowflakes don't stand much of a chance. Plus, December is only the beginning of the UK winter, meaning it's more likely to snow in January, February or even March than it is in December — but of course, that doesn't make for such a good Christmas card image.
When did it last snow in London at Christmas?
The last severely snowy spell in London and the south-east was March 2018's Beast From The East — but of course, that missed Christmas. For snowy festivities, we need to rewind back to December 2010. Much of the country was in the grip of a cold spell for most of December that year, with transport disrupted and flights at Heathrow, Gatwick and City Airports cancelled. Up to 25cm (10in) of snow fell in certain parts of the capital over Christmas week, meaning London woke up to a white (well, slushy grey) blanket on Christmas Day.
Meteorological service The Met Office sets a pretty low bar for the definition of a white Christmas; 'one snowflake to be observed falling in the 24 hours of 25 December somewhere in the UK'.
By that definition, half of all Christmasses are expected to be defined as 'white' in the UK; and the last time the UK had a white Christmas was 2020 — although none of it settled, and London didn't see any of the action.
What are the odds of a white Christmas this year in London?
Unlike the winter of 2019-2020, when we were repeatedly (and dramatically) warned of a chilly winter, similar weather warning haven't (yet) been issued for Christmas 2021 — and even if we were due 'Arctic blasts', that doesn't necessarily translate to a thick dusting of the white stuff. Your mum was right when she used to tell you it was 'too cold to snow'.
At time of writing in early December, William Hill has odds of 6/1 on a white Christmas in London (City Airport), the same as they were offering in 2019 (which turned out not to be a white Christmas), but realistically, the chances of an accurate forecast that far ahead are slim.
Of course, we won't know the real likelihood of a white Christmas 2021 until shortly before 25 December — The Met Office suggests five days in advance. But from our past experience, if you're preparing for a festive trip to London in the holiday season, you'd be better packing a raincoat than your snow boots.
Did it used to snow more in London?
Turns out Bing Crosby wasn't wrong — past Christmasses were probably whiter than those we experience now.
Winters in London used to be much colder. Just over 200 years ago, the River Thames would freeze so solidly that frost fairs were held atop its iced waters. London was in the grip of a 'mini ice age' at the time, which helped with all that freezing.
Changing climate isn't the only reason the Thames no longer freezes — the Victorians narrowed the river significantly by building embankments, meaning the water now runs much faster, so is much less likely to freeze over.
But yes, climate change is playing a large part in reducing snowy winters across the UK as a whole, including here in London. The coldest Christmas Day temperature ever recorded in England was a numbing -18.3°c in Durham back in 1878.