Libra runs from September 23 to October 22, the seventh sign of the zodiac and the second of the three air signs. Its symbol is the Scales, the only sign in the zodiac represented by an object rather than a person or an animal, and its ruling planet is Venus, paired here with a cardinal mode that opens the autumn season the way Aries opens spring.
Astrologers read that pairing as a shift in direction rather than a change in substance. Aries, Libra's opposite sign, starts the zodiac wheel focused on the self; Libra, six signs later, starts the second half of the wheel focused on the other, on negotiation, partnership, and how a person shows up once someone else is in the room. Fairness matters to Libra in a way that goes beyond etiquette: sources consistently describe the sign weighing both sides of an argument almost on reflex, sometimes past the point of being useful.
That weighing habit is where the Scales symbol earns its keep. Libra is often described as the diplomat of the zodiac, good at reading a room, smoothing tension, and finding the version of a plan that keeps the most people comfortable. The cost, sources note, is a real difficulty picking a side and sticking with it once the pros and cons stop being close to even.