Sumerian Zodiac by Date

Sumerian/Babylonian zodiac: tropical signs by date

Babylonia gave the 12-sign zodiac its structure around 3000 BCE, splitting the ecliptic into twelve 30° arcs. The traditional tropical date ranges we still use are these: Aries Mar 21 – Apr 20, Taurus Apr 21 – May 20, Gemini May 21 – Jun 21, Cancer Jun 22 – Jul 22, Leo Jul 23 – Aug 22, Virgo Aug 23 – Sep 22, Libra Sep 23 – Oct 22, Scorpio Oct 23 – Nov 21, Sagittarius Nov 22 – Dec 21, Capricorn Dec 22 – Jan 19, Aquarius Jan 20 – Feb 18, Pisces Feb 19 – Mar 20. So someone born May 15 lands on Taurus. One catch worth knowing: the precession of the equinoxes has nudged the real constellations by about a month since antiquity, which means a tropical Taurus today actually sits in front of the constellation Aries as far as an astronomer is concerned.

Applications

Traditional Western astrology, horoscope columns, and birth chart software all lean on it. So does cultural and historical research into Mesopotamian astronomy, comparative mythology, and any comparison with modern astronomy, which throws in a 13th constellation, Ophiuchus, that the ecliptic genuinely crosses but that the zodiacal twelve leave out.

FAQ

Is the zodiac scientifically valid? Astrology isn't a science. The zodiac is a cultural and symbolic system. Astronomy works with the same ecliptic, but it describes the constellations rather than using them to predict anything.

What is Ophiuchus? A 13th constellation the Sun passes through (≈Nov 29 – Dec 17). The Babylonians left it out so the calendar would stay at a tidy 12 signs, one per lunar month.

Why don't the dates match the real constellations? Earth's axis wobbles over a ~26,000-year cycle (precession). That drift moves the apparent sky by roughly one sign every 2,150 years, and it's been doing so since 3000 BCE.