Original: Under the tropical zodiac, the Sun enters Libra on the moment of autumnal equinox by definition on September 23, leaving it on October 22. Under the sidereal zodiac, it is currently there roughly around October 19 and November 16.
Simplified: In the tropical zodiac, the Sun meets Libra from September 23 to October 23, and in the sidereal zodiac, it ends on November 15.