Easter is the greatest of all Sundays, and Easter Time is the most important of all liturgical times. Easter Season is the celebration of the Lord's resurrection from the dead, culminating in his Ascension to the Father and sending of the Holy Spirit upon the Church.
The first eight days of Easter Time constitute the Octave of Easter and are celebrated as Solemnities of the Lord. The octave of Easter stretches from the first to the second Sunday and prolongs the joy of the initial day. In a sense, every day of the Octave is like a little Sunday.
There are 50 days of Easter from the first Sunday to Pentecost. The Sundays of this time of year are Sundays of Easter and are called, after Easter Sunday itself, the Second, Third, Fourth, Fifth, Sixth, and Seventh Sundays of Easter.
Traditionally, on the fortieth day after Easter the Ascension of the Lord is celebrated, except where, not being observed as a Holyday of Obligation, it has been assigned to the Seventh Sunday of Easter. (There are six metropolitan sees and their suffragan Dioceses which maintain the Solemnity of the Ascension on Thursday: Boston, Hartford, Newark, New York, Omaha, and Philadelphia.Every other region of the United States has opted to transfer the Solemnity to the Seventh Sunday of Easter).
The weekdays from the Ascension up to and including the Saturday before Pentecost prepare for the coming of the Holy Spirit, the Paraclete.