In recent years, a number of Protestant churches, led by Willow Creek Community Church in the Chicago suburbs, have begun to cancel their services on Christmas, suggesting that Christians should spend such an important day at home with their families rather than in church. The Catholic Church, however, takes a different approach.
Christmas Day is a Holy Day of Obligation in the Catholic Church. Because Christmas is a Holy Day of Obligation, all Catholics are required to attend Mass (or an Eastern Divine Liturgy) on Christmas Day. As with all Holy Days of Obligation, this requirement is so important that the Church binds Catholics to fulfill it under pain of mortal sin.
Of course, as with the requirement to attend Mass on every Sunday and Holy Day of Obligation, there are reasonable exceptions for those who are physically unable to attend, whether because of sickness, frailty, or the inability to travel to a Catholic church when Mass is being offered. The latter includes bad weather conditions; if in your judgment the weather is severe enough or the roads are in bad enough condition that you would be putting yourself or your family at risk by attempting to travel to a church for Mass on Christmas, your obligation to attend Mass is automatically dispensed.
Many people, of course, are away from home (and thus their home parishes) at Christmas to visit family and friends. Contrary to popular belief among Catholics, however, the mere fact of traveling does not dispense one from the requirement to attend Mass on Sundays or on Holy Days of Obligation like Christmas. If there is a Catholic church in the area in which you are traveling, your obligation to attend Mass remains. You may have to do a little research beforehand to find out when Mass will be held, but the internet makes that relatively easy nowadays.
If, however, the area in which you are traveling does not have a Catholic church, or if Mass is offered only during the only time you can travel, you are dispensed from your requirement to attend Mass on Christmas.
Christmas—the celebration of the birth of Jesus Christ—is the second most important feast in the entire liturgical year, behind only Easter Sunday, the celebration of Christ's Resurrection. Therefore, it is important for Christians to gather as one body and to worship Christ on this feast of His Nativity. As with the requirement to attend Mass every Sunday, attending Mass on Christmas is a way of professing our faith in Christ.