It is the time of the Vernal Equinox. The Sun enters the Sign Aries on March 20 at 17.32 UT (that’s 1:32 PM Eastern, 10:32 AM Pacific).
The longer night of the winter season is now in equal balance with daylight. From this point the length of daylight grows.
It is the beginning point of the Zodiac that astrologers use as measure. An astrological chart for the equinox moment is said to contain information relevant to at least the Spring season and perhaps for as much as the twelve months to follow.