December 21 zodiac sign
Cusp territory: on December 21 the Sun is either at 29° Sagittarius, the anaretic last degree, or has just crossed into Capricorn, depending on the birth year and time.
Sun signSagittarius or Capricorn
- Sun at 28°–30° Sagittarius
- 3rd decan · Sun
- Cusp birthday
December 21 in profile
There is no blended cusp sign in astrology, so a December 21 birthday is either Sagittarius or Capricorn, and the computed table on this page gives the answer. On the Sagittarius side the Sun sits in the final, anaretic degree, inside the Leo decan with the Sun as sub-ruler: the sign’s lessons arrive concentrated, with urgency. On the Capricorn side it stands at 0°, raw and new, doubly ruled by Saturn. Both versions share a wish to make vision count.
Ambition is the common thread. A Sagittarian December 21 aims wide and wants recognition; a Capricorn one aims high and wants proof. Both like a plan with a summit. In practice they set targets at the turn of each year, track them, and talk about them more openly than most. A job that leads nowhere visible rarely holds them for long. Each birthday doubles as a private review of the year’s progress.
First impressions differ slightly by sign. The Sagittarian version arrives warm, curious and quick to joke; the Capricorn version arrives composed, observant and dryly funny. Both are judged capable within minutes. For either sign, it pays to let people see the softer side earlier than feels comfortable, since trust grows faster when competence comes with some warmth.
Sagittarius or Capricorn?
The Sun moves from Sagittarius into Capricorn around December 21, and the exact moment shifts from year to year. Between 1930 and 2040 it happened during the UTC day of December 21 in 50 years out of 111, at a median of 18:13 UTC (17:46 UTC in births from 1980 to 2010). In 61 years the whole day was still Sagittarius. So a December 21 birthday is Sagittarius or Capricorn depending on the year and the time, never a blend of the two.
The Sun on December 21, year by year (UTC)
- 1970Sagittarius all day
- 1971Sagittarius all day
- 1972Capricorn from 18:13
- 1973Sagittarius all day
- 1974Sagittarius all day
- 1975Sagittarius all day
- 1976Capricorn from 17:35
- 1977Capricorn from 23:23
- 1978Sagittarius all day
- 1979Sagittarius all day
- 1980Capricorn from 16:56
- 1981Capricorn from 22:51
- 1982Sagittarius all day
- 1983Sagittarius all day
- 1984Capricorn from 16:23
- 1985Capricorn from 22:08
- 1986Sagittarius all day
- 1987Sagittarius all day
- 1988Capricorn from 15:28
- 1989Capricorn from 21:22
- 1990Sagittarius all day
- 1991Sagittarius all day
- 1992Capricorn from 14:43
- 1993Capricorn from 20:26
- 1994Sagittarius all day
- 1995Sagittarius all day
- 1996Capricorn from 14:06
- 1997Capricorn from 20:07
- 1998Sagittarius all day
- 1999Sagittarius all day
- 2000Capricorn from 13:38
- 2001Capricorn from 19:21
- 2002Sagittarius all day
- 2003Sagittarius all day
- 2004Capricorn from 12:42
- 2005Capricorn from 18:35
- 2006Sagittarius all day
- 2007Sagittarius all day
- 2008Capricorn from 12:04
- 2009Capricorn from 17:46
- 2010Capricorn from 23:38
- 2011Sagittarius all day
- 2012Capricorn from 11:12
- 2013Capricorn from 17:11
- 2014Capricorn from 23:03
- 2015Sagittarius all day
- 2016Capricorn from 10:44
- 2017Capricorn from 16:28
- 2018Capricorn from 22:22
- 2019Sagittarius all day
- 2020Capricorn from 10:03
- 2021Capricorn from 15:59
- 2022Capricorn from 21:48
- 2023Sagittarius all day
- 2024Capricorn from 09:20
- 2025Capricorn from 15:03
- 2026Capricorn from 20:50
- 2027Sagittarius all day
- 2028Capricorn from 08:20
- 2029Capricorn from 14:14
- 2030Capricorn from 20:10
Calculated by Lunonis from the same ephemeris code as our charts (astronomy-engine, checked against Swiss Ephemeris): geocentric, tropical zodiac, true equinox of date. Times are UTC: add or subtract your time zone’s offset, which can move the change to the day before or after.
Your Moon sign depends on the year
The Sun is in the same place on December 21 every year; the Moon is not. It changes sign every two and a half days, so people who share this birthday can have any of the twelve Moon signs. Here is where it was on December 21 in recent years, from 00:00 to 23:59 UTC (an arrow means it changed sign during the day).
- 2017Capricorn → Aquarius
- 2018Gemini
- 2019Libra → Scorpio
- 2020Pisces → Aries
- 2021Cancer → Leo
- 2022Scorpio → Sagittarius
- 2023Aries
- 2024Virgo
- 2025Capricorn
- 2026Taurus → Gemini
Compatible signs for a Sagittarius
Sun-sign compatibility starts from the element. Sagittarius gets on most easily with its own element and with the two sextile signs, and feels the strongest pull from its opposite. For a December 21 birthday, in the Leo decan, Leo is a natural match. The full charts decide how a real pairing feels.
A gift for a December 21 birthday
A good hiking day pack and a planned walk to a summit with a view, the kind of goal both a Sagittarius and a Capricorn can enjoy reaching.
Asked about December 21
What zodiac sign is December 21?
December 21 can be Sagittarius or Capricorn. The Sun changed from Sagittarius to Capricorn during this date in 50 of the 111 years from 1930 to 2040, so the answer depends on the birth year, time and place. The year-by-year list above shows when; a birth chart gives the exact answer.
Is December 21 a cusp birthday?
Yes. December 21 is one of the days the Sun leaves Sagittarius for Capricorn. People call it the Sagittarius–Capricorn cusp, but there is no blended sign: someone born before the change is Sagittarius, after it Capricorn.
What decan is December 21?
December 21 falls in the 3rd decan of Sagittarius. In the triplicity system we use, that decan belongs to Leo and its ruler Sun, which colours the Sagittarius Sun with a little of Leo.
Your birthday is only the Sun
A December 21 birthday tells you where the Sun was. The Moon, the Rising sign and eight more planets each sit somewhere of their own, and they depend on the year, the hour and the place. The free calculator shows all of them.