Mark your calendars, because Saturday, September 22 is a super important date. It's the autumnal equinox, the first official day of fall, and most importantly the start of Libra season. And really, the Libra's fall equinox 2018 horoscope is wildly positive and optimistic. As a Libra who loves everything about autumn, I could not be more thrilled to share this info.

Whatever your sign, the fall equinox is a pretty cool event. Occurring every year between September 21 and 24, the autumnal equinox marks the first official day of fall in the northern hemisphere, as well as the time in which day and night are almost equal length, as noted on History.com. (The vernal equinox in March also features an almost-equal length of day and night.) From this day forward, the nights start getting longer than the days as autumn slowly moves into winter.

But really, the start of Libra season is the best part about this day. The sign of the scale, Libras are born between September 23 and October 22, according to Astrology Zodiac Signs. Valuing kindness and harmony, people with this sign are all about keeping the peace, according to Horoscope.com

So what does it mean when autumn and Libra season kick off on the same day? Basically, everything's coming up Libra for the next few days. To learn more about it, Romper spoke with astrologer and spiritual guide Dr. Craig Martin, who has 25 years of experience in the field. He shared great insight about the way the equinox affects this (and really every) sign.