December 21 Zodiac Sign: Sagittarius or Capricorn?

December 21 is a cusp birthday: in 57 of the 87 years from 1940 to 2026 the Sun entered Capricorn during December 21 (US Eastern Time), so people born that day are Sagittarius before the change time and Capricorn after it; in 30 years the change came later and the whole day was Sagittarius. Your sign depends on the year and time of birth — see the table. Pacific Time: change during the day in 67 years, whole day Capricorn in 0, whole day Sagittarius in 20.

December 21 at a glance

• Possible Sun signs: Sagittarius before the change, Capricorn after
• Elements: Fire (Sagittarius), Earth (Capricorn)
• Modalities: Mutable (Sagittarius), Cardinal (Capricorn)
• Rulers: Jupiter (Sagittarius), Saturn (Capricorn)
• Data: NASA JPL Horizons, 1940–2030

In 1966 Capricorn arrived at 23:28 PST on December 21 in California; New York recorded the same minute as 02:28 EST on December 22. That year only the West Coast saw the change during December 21. Because the two coasts can land on different dates, the table gives each its own change time: go to your birth year and take the time printed for your own coast. With a time listed, a birth before it falls under Sagittarius and a birth from that minute under Capricorn; with no change time for your coast, the Sun never left Sagittarius that December 21. Chicago and Denver times are not in the table; for births there, use the birth chart below. Day-by-day signs for the whole month sit under December zodiac signs.

Between 1940 and 2026, late Pacific evenings gave the date a change in years when Eastern clocks had none: 1941, 1945, 1966, 1970, 1974, 1978, 1999, 2003, 2007 and 2011. Each of those changes came after 9 p.m. PST, from 21:04 (1945) to 23:44 (1999), which was already past midnight on Eastern clocks. The War Time row is 1944, with 19:15 EWT and 16:15 PWT read on clocks set forward one hour, as they were across the US from February 9, 1942, to September 30, 1945.

Two situations call for the birth time: a December 21 change on your coast in your birth year, and a birthplace the table leaves out. Type the date, the time and the city into the birth chart to check your Sun sign with your birth time; it is a free tool, and no sign-up stands between you and the result. Without a birth time, the chart is calculated for 12:00 noon and marked as such.

Instead of relying on a single noon position, the calculator checks for any sign changes across your entire local birth date. If the Sun, the Moon, or another planet changes sign during that local day, the result shows each possible sign for that day rather than guessing a single one.

Take the descriptions below as astrology's own vocabulary for the two signs; astrology is an interpretive tradition, not a scientifically validated method.

Sagittarius, the sign in place before the switch, is a Fire sign. The old descriptive words for Fire run hot, dry and ardent, and in polarity Sagittarius is positive, or active, in the tradition's terms. Astrology links its ruler, Jupiter, with adventures, foreign travel and the law. Its symbol, dates and longer reading wait on the Sagittarius zodiac sign page.

From the change minute, Capricorn takes over, and with it Earth, whose words in the tradition are heavy, cold and dry. Negative polarity arrives as well, under its other names yin or passive. Saturn, the ruling planet, stands in astrology for civility, protective roles and an economical nature. Capricorn in full, symbol and dates included, is on the Capricorn zodiac sign page.

FAQ

If December 21 is a cusp birthday, which sign does the day start in? Sagittarius, by Eastern and Pacific clocks: across 1940–2030, neither New York nor Los Angeles ever starts December 21 with the Sun in Capricorn. People call such dates "cusp" birthdays because the Sun can switch signs during them, yet the switch is a single instant, so each birth gets one Sun sign. Capricorn is the answer for an Eastern or Pacific Time birth only if the Sun's entry into Capricorn came on that local date, no later than the minute of birth; any other December 21 birth on those clocks stays Sagittarius.

What time does the Sun change sign on December 21? The clock time differs with the year, and some years have no December 21 change at all. For birth years 1940–2026, the Eastern change times on this date range from 04:21 EST (2024) to 23:48 EST (2015); on the Pacific side the span is 01:21 PST (2024) to 23:44 PST (1999). If the change on a coast came only after December 21 had ended there, that whole date was Sagittarius.

How this page was made

Astrolivo's editorial team prepared and fact-checked the text. Each change minute was computed from NASA JPL Horizons ephemeris data for 1940–2030 and converted to New York and Los Angeles clock time under the IANA time zone rules, War Time included. The element words, polarity labels and planet themes were checked against Wikipedia's "Astrology and the classical elements," "Astrological sign" and "Planets in astrology," and the science sentence against "Astrology and science"; descriptions of the signs follow the astrological tradition.