December


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December is the twelfth and final month of the year in the Julian and Gregorian Calendars and is the seventh and last of seven months to have a length of 31 days.

December, from the Très Riches Heures du duc de Berry

December got its name from the Latin word decem (meaning ten) because it was originally the tenth month of the year in the calendar of Romulus c. 750 BC which began in March. The winter days following December were not included as part of any month. Later, the months of January and February were created out of the monthless period and added to the beginning of the calendar, but December retained its name.[1]

In Ancient Rome, as one of the four Agonalia, this day in honor of Sol Indiges was held on December 11, as was Septimontium. Dies natalis (birthday) was held at the temple of Tellus on December 13, Consualia was held on December 15, Saturnalia was held December 17–23, Opiconsivia was held on December 19, Divalia was held on December 21, Larentalia was held on December 23, and the dies natalis of Sol Invictus was held on December 25. These dates do not correspond to the modern Gregorian calendar.

The Anglo-Saxons referred to December–January as Ġēolamonaþ (modern English: "Yule month"). The French Republican Calendar contained December within the months of Frimaire and Nivôse.

Astronomy

Month December depicted in Hans Bol's and Adriaen Collart's Emblematica Evangelica.

December contains the winter solstice in the Northern Hemisphere, the day with the fewest daylight hours, and the summer solstice in the Southern Hemisphere, the day with the most daylight hours (excluding polar regions in both cases). December in the Northern Hemisphere is the seasonal equivalent to June in the Southern Hemisphere and vice versa. In the Northern hemisphere, the beginning of the astronomical winter is traditionally 21 December or the date of the solstice.

Meteor showers occurring in December are the Andromedids (September 25 – December 6, peaking around November 9), the Canis-Minorids (December 4 – December 15, peaking around December 10–11), the Coma Berenicids (December 12 to December 23, peaking around December 16), the Delta Cancrids (December 14 to February 14, the main shower from January 1 to January 24, peaking on January 17), the Geminids (December 13–14), the Monocerotids (December 7 to December 20, peaking on December 9. This shower can also start in November), the Phoenicids (November 29 to December 9, with a peak occurring around 5/6 December), the Quadrantids (typically a January shower but can also start in December), the Sigma Hydrids (December 4–15), and the Ursids (December 17-to December 25/26, peaking around December 22).