March Equinox in Plano, Texas, U.S.A. is on Saturday, March 19, 2016 at 11:30 PM CDT. The March equinox or Northward equinox is the equinox on the earth when the Sun appears to leave the southern hemisphere and cross the celestial equator, heading northward as seen from earth. In the northern hemisphere the March equinox is known as the vernal equinox, and in the southern hemisphere as the autumnal equinox. On the equinoxes the Sun shines directly on the equator and the length of day and night is nearly equal. This also signals the first day of Spring for the Northern Hemisphere or the first day of Fall in the Southern Hemisphere.
In 325CE the Council of Nicaea established that Easter would be held on the first Sunday after the first full moon occurring on or after the vernal equinox.