Liturgical Notes for Easter
From Universal Norms on the Liturgical Year and the Calendar:
The fifty days from the Sunday of the Resurrection to Pentecost Sunday are celebrated in joy and exultation as one feast day, indeed as one "great Sunday." These are the days above all others in which the Alleluia is sung. The Sundays of this time of year are considered to Sundays of Easter and are called, after Easter Sunday itself, the Second, Third, Fourth, Fifth, Sixth, and Seventh Sundays of Easter. This sacred period of fifty days concludes with Pentecost Sunday.
The first eight days of Easter Time constitute the Octave of Easter and are celebrated as Solemnities of the Lord.
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 (cf. no. 7).
The liturgical color for Easter is white.The General Instruction of the Roman Missal (no. 346) also states: On more solemn days, festive, that is, more precious, sacred vestments may be used even if not of the color of the day. The colors gold or silver may be worn on more solemn occasions in the Dioceses of the United States of America."
Especially during Easter Time, instead of the customary Penitential Act, the blessing and sprinkling of water may take place as a reminder of Baptism.
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 following Sunday (the Seventh Sunday of Easter).
This was taken from the US Conference of Catholic Bishops website - USCCB