December (listen) is the twelfth and last month of the year in the Gregorian Calendar and one of seven Gregorian months with the length of 31 days.

December begins (astrologically) with the sun in the sign of Sagittarius and ends in the sign of Capricorn. Astronomically speaking, the sun begins in the constellation of Ophiuchus, which is the only zodiacal constellation that is not counted as an astrological sign, and ends in the constellation of Sagittarius.

In Latin, decem means "ten". December was also the tenth month in the Roman calendar until a monthless winter period was divided between January and February. December's flower is the narcissus or holly. December's birthstones are turquoise, lapis lazuli, zircon, topaz (blue), or tanzanite. It is Seasonal Depression Awareness Month. December is the month with the shortest daylight hours of the year in the Northern Hemisphere and the longest daylight hours of the year in the Southern Hemisphere