December 2025: darkest night, shortest day
December 2025 opened on a Monday, closed on a Wednesday and stacked five each of Mondays, Tuesdays and Wednesdays along the way. Then, in the final third, it served the year's darkest night and its shortest day back to back. The new moon fell on Saturday 20 December; the winter solstice on Sunday 21. The light started its return before the month was even finished. Thirty-one days, 23 of them business days, all accounted for.
Weeks 49 to 52, then week 1
December closed one year's week count and opened the next's: ISO weeks 49, 50, 51 and 52, then week 1 of 2026, all inside 31 days. The handover fell on Monday 29 December, whose week runs on into January. No printing error: under ISO rules, week 1 of a year is the week containing its first Thursday. This time, that Monday belonged to 2025.
The Cold Moon, December's full moon and the highest-riding of the year, rose on Thursday 4 December. The last quarter came on Thursday 11, and the first quarter of the returning light on Saturday 27. The year itself ended on Wednesday 31 December, with 2026 beginning the following day, on a Thursday.
One Friday, two redraws
Friday 5 December rearranged two industries before dinner. Netflix agreed to pay $72 billion for Warner Bros.' studios and the HBO Max streaming service, splitting the old studio from its cable networks. Hours later in Washington, the first World Cup draw for the expanded 48-team field set the twelve groups. The US, Canada and Mexico will host the summer 2026 tournament.
The screens kept their appointments. The third Pandora film, Avatar: Fire and Ash, opened worldwide on Friday 19 December and grossed roughly $345 million over its opening weekend. The Game Awards fell on Thursday 11 December, and Clair Obscur: Expedition 33 collected a record nine trophies there, Game of the Year among them. The final episode of Stranger Things, nearly two hours long, landed on Wednesday 31 December, with simulcast screenings in cinemas.
A heavy first week
The month opened in catastrophe. The month's first week brought monsoon floods and landslides across Indonesia, Malaysia, Thailand and Sri Lanka. More than 1,100 people died, with Sumatra and northern Sri Lanka hit worst. The totals took days to settle, and they were terrible when they did.
An earthquake of magnitude 7.6 shook the sea floor off northern Japan on Monday 8 December. It injured dozens and lifted tsunami waves of roughly 70 cm on the coast. Two days later, on Wednesday 10 December, Australia began enforcing the world's first ban on social media for under-16s. Oslo hosted the Nobel ceremony that day, at which Maria Corina Machado's daughter collected her mother's Peace Prize.
The year ended on a Wednesday, and 2026 began on the Thursday, briskly, as if nothing had happened. A blank January grid was already waiting.