"Today"
Prayer in the events of each day and each moment is one of the secrets of the kingdom revealed to "little children," to the servants of Christ, to the poor of the Beatitudes. It is right and good to pray so that the coming of the kingdom of justice and peace may influence the march of history, but it is just as important to bring the help of prayer into humble, everyday situations; all forms of prayer can be the leaven to which the Lord compares the kingdom.
Source: Catechism of the Catholic Church (Vatican.va)