You probably know that the winter solstice, which falls on Sunday, 21 December in 2025, is the shortest day of the year.
It marks the start of winter in the astronomical calendar, though the meteorological calendar always says winter starts on 1 December.
That discrepancy exists because the meteorological calendar, which has 365 days in a year, doesn’t quite map onto the astronomical calendar (365.2422 days a year). It’s also why the winter solstice doesn’t always fall on the same date.
But to be completely honest, I thought until recently that the term only referred to the duration of light on that day.
As it turns out, though, solstice is a distinct astronomical event, which The Met Office said “is a very specific moment which is over almost as soon as it has begun”.
Even its name has origins I wasn’t aware of.
What does “solstice” actually mean?
“Solstice” comes from the Latin word “solistum”. This means “sun standing still”.
That’s because, in the actual moment of the solstice, the sun appears to stall in the sky.
The winter solstice occurs when the sun is exactly over the Tropic of Capricorn, the Met Office said.
Or, as Dr Darren Baskill, Lecturer in Physics and Astronomy from the University of Sussex, shared, it’s the moment the North Pole points away from the sun.
“The Earth is tilted (at 23.5 degrees) such that the North Pole always points towards the star Polaris,” he said.
“On the summer solstice, the North Pole points over the Sun. Six months later, on the winter solstice, when the Earth has moved to the other side of the solar system, the North Pole is pointing away from the Sun.”
The Met Office said that this year in the UK, the event will happen at 9:21, December 21.
But the exact minute will change according to your time zone and place in the world.
How did we celebrate the winter solstice?
The word “Yule” actually comes from the Scandinavian festival of Juul. Logs were lit to commemorate the sun, hence “Yule log”.
But that is one of many solstice celebrations. Take the Ancient Roman Saturnalia, or the thousands of years-old Newgrange monument in Ireland, which has a passage exactly designed to allow light through on the winter solstice.
Similar celebrations take place around the world, the BBC said.
The winter solstice means that the days will start getting longer, and the nights shorter. Anyone who’s faced the sub-4pm sunsets we’re dealing with at the moment may still find the event worthy of celebration.
