Tradition

January 21 Zodiac Sign

Tradition: Western astrology. A tradition, not a forecast. Astrologers read it this way; the evidence does not.

By Suraj Giri

January 21 is Aquarius on the dates most calendars use (January 20 to February 18). From 1950 to 2029, every birth hour on January 21 in US Eastern time fell in Aquarius.

Check a January 21 Aquarius against any sign

January 21 zodiac compatibility

By this site's zodiac points method, a January 21 Aquarius scores highest with Gemini and Libra, a strong match at 8 of 8 points, then Aries and Sagittarius, a good match at 5 of 8.

PairVerdictPointsAspect
Gemini and Aquariusstrong match8 of 8trine
Libra and Aquariusstrong match8 of 8trine
Aries and Aquariusgood match5 of 8sextile
Sagittarius and Aquariusgood match5 of 8sextile

who a January 21 Aquarius is compatible with

Today's Aquarius love horoscope

Have your partner's birthday? Compare January 21 with your partner's birthday.

Scores come from this site's zodiac points method (formula 1.1), reviewed by Jahben R., astrologer, on 2026-09-23. How it works is on the methodology page.

Aquarius at a glance for a January 21 birthday

  • Element: air
  • Modality: fixed
  • Ruler: Uranus (traditionally Saturn)
  • Position: day 2 of 30 of Aquarius
  • Next sign: Pisces, from February 19
  • The Sun, 1950 to 2029 (US Eastern time): 0.1 to 2.5 degrees of Aquarius

January 21 decan (Tradition)

In the triplicity system of decans, a tradition, January 21 falls in the first decan of Aquarius (0 to 10 degrees), ruled by Uranus (traditionally Saturn).

The older Chaldean system of decans assigns different rulers.

Famous people born on January 21

  • Paul Allen, businessperson, born 1953
  • Plácido Domingo, opera singer, born 1941
  • Christian Dior, fashion designer, born 1905
  • Geena Davis, actor, born 1956
  • Trương Tấn Sang, politician, born 1949

Birth dates from Wikidata (CC0), fetched 2026-09-26.

A note on January 21 birthdays

Two days into Aquarius, this date sits at 0.1 to 2.5 degrees, in the sign's first decan of the triplicity system, ruled by Uranus and traditionally Saturn. By this site's points method, Gemini is read as Aquarius's strongest match, a trine worth 8 points, with Aries following as a good sextile match worth 5. The tradition reads Uranus as independence and change, a fitting note for how this fixed air sign tends to approach a new connection: on its own terms, without being rushed.

Questions people ask

What zodiac sign is January 21?
Aquarius. January 21 falls in Aquarius' dates on most calendars, January 20 to February 18, as day 2 of 30 of Aquarius.
Who is a January 21 Aquarius most compatible with?
By this site's zodiac points method, a January 21 Aquarius scores highest with Gemini and Libra (a strong match, 8 of 8 points), then Aries and Sagittarius (a good match, 5 of 8).
Does the birth year change the zodiac sign for January 21?
Not from 1950 to 2029 in US Eastern time: January 21 was Aquarius for every birth hour in all 80 years. For other years or time zones, use the calculator on the zodiac sign dates page.

Birthdays around January 21

Sources