A surprising and unseasonal wave of warm weather has left Britons sweltering in winter clothing and turning off their central heating, sparking widespread confusion and chatter across social media.
Social Media Baffled by Balmy December
As temperatures in London climbed to a mild 12°C (53.6°F), many took to platforms like X and TikTok to express their bewilderment. One user questioned, 'Is nobody concerned with how WARM it is in the middle of December for London?', capturing the mood of hundreds. Another commented, 'I hate the cold but it's so concerning that it's not actually been that cold this autumn/winter.'
The sentiment was echoed by others enjoying the unusual conditions, with one person stating, 'I'm literally walking around with no coat on bc im so hot lol.' Many noted a longer-term trend, with one observer remarking, 'It does seem like Decembers have got noticeably milder in the last few years... White Christmases seem like a distant memory now.'
These reactions come as the UK experiences temperatures significantly above the typical December range of 2°C to 8°C (35–46°F). Some areas have even seen the mercury rise as high as 15°C (59°F) in the first half of the month.
The Meteorological Cause: A Supercharged Jet Stream
Meteorologists have now pinpointed the reason behind the warm pre-Christmas spell. According to Jim Dale, senior meteorologist at British Weather Services, the UK is under the influence of an unusually strong and energetic North Atlantic jet stream.
This high-altitude river of air, flowing five to seven miles above the ground, has been steering a succession of low-pressure systems and mild Atlantic air directly towards Britain. 'One of the reasons we're getting that is because of the cold weather in the northeastern United States and Canada,' explains Mr Dale. 'When that cold air meets mild air over the Atlantic, it energises the jet stream, which produces these low-pressure systems.'
This pattern has not only brought warmth but also the recent barrage of heavy rainfall, strong winds, and storms like Storm Bram, which caused flooding in areas such as York.
A Cooler Christmas on the Horizon?
There is potential relief for those missing seasonal chill. Forecasts from the Met Office indicate a change is likely. 'A large area of high pressure is expected to build closer to the UK from around the 22nd of December,' their outlook states. This should bring calmer, drier conditions and an increased chance of overnight frost and fog, meaning Christmas Day itself could be drier and somewhat colder than the preceding weeks.
However, meteorologists also contextualise this warm spell within broader climate trends. While not directly attributable to climate change without a formal study, a Met Office spokesperson confirmed that human-induced climate change makes warmer winter weather more frequent. Notably, six of the ten warmest UK winters on record have occurred since the year 2000.
The spokesperson added, 'This obviously doesn’t mean that we won’t see colder periods, but that the background influence of global warming means we generally see warmer winters than we used to.' This aligns with global projections, with 2025 already tracking to be one of the three hottest years ever recorded.
