December has two zodiac signs: Sagittarius until 21 December, and Capricorn from 22 December.

| Born | Sign | Constellation · brightest star |
|---|---|---|
| 1–21 December | Sagittarius | Sagittarius · Kaus Australis |
| 22–31 December | Capricorn | Capricornus · Deneb Algedi |
These are the usual calendar dates. The moment the Sun moves from Sagittarius into Capricorn shifts slightly between years, so a birthday on the boundary can fall either side. A birth chart calculated for the exact minute and place shows where the Sun stood.
Sagittarius covers 22 November – 21 December. Its constellation is Sagittarius, and its brightest star is Kaus Australis.
From the UK, Sagittarius is best placed in the evening sky in July and August, very low in the south.
Capricorn covers 22 December – 19 January. Its constellation is Capricornus, and its brightest star is Deneb Algedi.
From the UK, Capricornus is best placed in the evening sky from August to October, low in the south.
Each person is drawn as the constellation of their sign, from the familiar calendar dates. Everyone born 1–21 December appears as Sagittarius, with Kaus Australis named; everyone born 22–31 December as Capricorn, with Deneb Algedi named. Two to six people — first names and birthdays only.
December has two zodiac signs: Sagittarius until 21 December and Capricorn from 22 December.
In the usual calendar dates, 22 December is the first day of Capricorn. The exact moment the Sun moves into the next sign shifts slightly from year to year, so a birth on 21 or 22 December can fall either side.
The constellation Capricornus, whose brightest star is Deneb Algedi.
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