Easter is early this year and is Sunday March 31st. How do we know when Easter Sunday will be? Here is the way to figure it out. Easter occurs on the first Sunday following the full moon after the vernal equinox (otherwise known as the first day of spring). So this year the vernal equinox falls on the 20th of March when the sun enters the sign of Aries and the full moon falls on the 27th of March therefore the first Sunday after is March 31st. Any questions?