December closes out the year with 31 days, and its name comes from the Latin “decem,” meaning ten — a leftover from the older Roman calendar in which December was the tenth month, before January and February were added to the start of the year.
The Northern Hemisphere’s winter solstice falls in late December, the shortest day and longest night of the year, after which daylight slowly begins to lengthen again. At the same moment, the Southern Hemisphere experiences its summer solstice — the longest day of the year there — putting December at the peak of summer in countries like Australia and Brazil even as the Northern Hemisphere settles into winter.
December is one of the most holiday-dense months on the calendar. Christmas is celebrated on December 25th in many countries around the world, Hanukkah falls in November or December depending on the Hebrew calendar, and December 31st is New Year’s Eve, marking the final countdown to the new year. This clustering of celebrations, combined with the Northern Hemisphere’s cold, dark evenings, gives December its strong identity as a month of gathering, reflection, and festivity.