Easter is the season of the celebration of the resurrection of Christ. The Sunday Gospel lessons are of the appearances of Christ after his resurrection on Easter Sunday.
The color of the season is white. This season is 50 days long and includes the feast of the Ascension. There are seven Sundays in Easter. The Easter season closes at Pentecost Sunday or Whitsunday.
The date of Easter Sunday determines the date of Ash Wednesday. It determines the length of the Season after the Epiphany and the Season after Pentecost. It is the first Sunday after the first full moon after the vernal (Spring) equinox. For simplicity, there is a table on page 883 of the Book of Common Prayer.
The lessons for Easter Sunday are the same each year.