Why December’s Not the 10th Month

December is the 12th month (and last month) in our modern-day Gregorian calendar (as it was in the preceding Julian calendar). However, it was initially the 10th month of the Roman calendar (until 153 BC). Hence, “December” comes from the Latin decem, meaning “ten.”

In Roman times, the calendar only had ten months and began with March! The winter period was not even assigned months because it was not an active time for military, agriculture, or civil life.

The month of December originally consisted of 30 days. After January and February were added to the calendar (around 700 BCE), December was shortened to 29 days. Then, two days were added to December in the subsequent Julian calendar, making it 31 days long.

Odd Moments This Month in History

December 14, 1807: Space Invader

At 6:30 a.m. on this day in 1807, residents from Vermont to Connecticut looked up at the sky and saw a red fireball. About two-thirds the size of a full Moon, it raced across the heavens, broke apart, and fell to earth in at least six areas of Weston (now Easton), Trumbull, and Fairfield, Connecticut. Whizzing sounds were heard close to the impact sites, and three sonic booms were heard as far as 40 miles away. The entire event took about 30 seconds.

Upon hearing the news a few days later, Yale professor Benjamin Silliman and his colleague, professor James Kingsley, traveled to the impact area to talk to witnesses, examine impact sites, and collect specimens (including some that enterprising townsfolk were selling as souvenirs). Silliman confirmed it was a meteorite—the first officially recorded in the New World.

Meteorites, rocks that fell from space, were a concept slowly gaining acceptance in Europe, but their study was still a relatively new science. In an article in the Connecticut Herald published on December 29, Silliman and Kingsley described the Weston event. The news rapidly spread to other newspapers, and accounts were published in literary and philosophical journals. Later, Silliman performed a chemical analysis of the rocks and published a revised report. Notable scientific organizations in Philadelphia, London, and Paris discussed the findings. Still, there were skeptics about the idea of meteorites, including U.S. President Thomas Jefferson, who said, “It is easier to believe that two Yankee professors could lie than to admit that stones could fall from heaven.” 

Winter Solstice

The month of December brings the winter solstice in the Northern Hemisphere. This is the shortest day of the year (the day with the least amount of daylight). 

December Holidays

• December 1 is the First Sunday of Advent, marking the beginning of the Advent season.

• December 6 is Saint Nicholas Day. The patron saint of children is the model for Santa Claus and gift-giving. 

• December 7 is National Pearl Harbor Remembrance Day.

• December 8 is Bodhi Day in the Buddhist calendar, celebrating Buddha’s enlightenment; it’s celebrated in a way that’s similar to how Christians celebrate Christmas to honor Jesus Christ. 

• December 13 is St. Lucia’s Day, which has long been associated with festivals of light. Before the Gregorian calendar reform in 1752, her feast day occurred on the shortest day of the year (hence the saying “Lucy light, Lucy light, shortest day and longest night”).

• December 15 is Bill of Rights Day.

• December 17 is Wright Brothers Day.

• December 21 is the Winter Solstice—the astronomical day when the hemisphere is tilted as far away from the Sun as possible. Starting in ancient times, people celebrated the rebirth of the Sun event through Yule.

• December 25 is Christmas Day, a Christian holiday commemorating the birth of Jesus Christ. Learn more about American Christmas traditions.

• December 25 also marks the beginning of  Hanukkah this year, the 8-day Jewish festival of lights. 

• December 26 is Boxing Day (Canada, UK) and the first day of Kwanzaa.

• On the last evening of the year, December 31, kiss the person you hope to keep kissing! Discover New Year’s traditions from around the world.