The sign for December 1 through December 21 is Sagittarius. The sign for December 22 through December 31 is Capricorn.
Sagittariuses are described as upbeat with a loyal nature. They tend to look at the positive in things regardless of how bleak the situation looks.
Capricorns are supposed to be upfront and honest. They have no issues with expressing their feelings, and they tend to be creative and figure out how to get complicated tasks done.
Some people fall in the cusp of the two signs; in these cases, the people are believed to contain characteristics of both the signs.