September 22 Equinox ~ when the sun crosses over the Earth’s equator and night and day are approximately equal
The September Equinox heralds the first day of autumn for the Northern Hemisphere and, the first day of Spring for the Southern Hemisphere. At an equinox, the sun appears directly above the Earth’s equator. During the September equinox, the sun crosses from north to south. Day and night are equal in length at each equinox. The sun will enter the zodiac sign of Libra, ruled by the goddess of love; she seeks harmony, beauty, and social connection.
Mundane astrologers cast charts for the exact moment of equinoxes and solstices to understand what might happen for the following three months. I like to check the AstroCartography or locational astrology for all Equinox and Solstice charts to see trends and world events.
AstroCartography was pioneered and popularized by the astrologer Jim Lewis in the 1970s. The system uses astrology, astronomy, and geography to compare your natal chart, or a mundane event to a map of the Earth. The map shows each planet and its geographical position at the time of an event. For example, Mars might have been above the town where you were born. At that location you will feel more Mars; you might be more aggressive, argumentative, and competitive than if you lived under a Moon influence which would be fickle and emotionally sensitive. To complete the picture you have to factor in what houses and aspects are influencing the planet (s) that you are living under. AstroCartography is fun and very helpful.
The Autumn Equinox chart contains a waning but auspicious configuration called a Kite. The Kite occurred on 9/20 and included the Sun and the outer planets, Neptune in Pisces, Pluto in Capricorn, and Uranus in Taurus, all three outer planets are in the last degrees of their signs. In 2025 the configuration will resurface but each outer planet will have moved forward into new signs, and the focus will shift to fire and air signs. An outer planet Kite indicates that world events are changing and 
will be moving in new directions.
The United States national election comes several weeks after the Autumn Equinox. The Autumn Equinox chart holds some interesting insights related to the upcoming election.
I will do a separate post about the upcoming US election if you are interested. I just wanted to let you know that what I have to say is not for the faint of heart.