The official lighting ceremony of the National Christmas Tree takes place on the first Thursday of December. However, the event also marks the beginning of a month-long series of events and activities celebrating the holiday season. From concerts and holiday markets to special exhibits and tree-lighting ceremonies in different parts of the city, there's always something going on during this festive time of year. So, no matter when you choose to visit the National Christmas Tree, you're sure to find plenty of holiday cheer.