It's the 26th International Astrology Day! (An approximately 24-hour period that began at 5:58 pm EST yesterday with the equinox). And perfect timing this year with the full, bright and fabulous "super worm moon" also happening at the equinox.
It's no surprise that this is a meaningful time, historically, to celebrate the beginning of spring and a new year. If you're curious what the next year will bring in your life, a solar return reading is a nice way to celebrate you.
According to Wikipedia:
International Astrology Day is the first full day of the astrological sign of Aries and thus marks the beginning of the tropical Zodiac. It is celebrated/observed depending on the exact day that the Northward equinox actually occurs. This varies year to year between March 19–22, though it usually falls on March 20 or March 21.
The date of the holiday occurs at the same time of the Iranian new year (Norouz), which is celebrated in many places throughout the Middle East and Central Asia. It also corresponds with the beginning of the Bahá'í calendar, which is celebrated as Bahá'í Naw-Rúz. Other holidays occurring around this time include Ostara (amongst neopagans), Chunfen in China, and Vernal Equinox Day (a public holiday in Japan), among others.