Ordinary Time occurs just after Christmas season, and then again just after Easter. It covers a large period at the end of winter, through the entirety of spring and summer, and into mid-fall. It is the entirety of the year outside of Advent, Christmas, Lent, and Easter.
The name of Ordinary Time does not denote that there is something less special, or in other words the common meaning that we give to the word 'ordinary'. Instead it draws its name from the word 'ordinal', which means 'numbered', because the Sundays that make up Ordinary Time are indeed numbered.
During this time all the days, but especially the Sundays, are devoted to the mystery of Jesus Christ in every aspect of His existence. The first Ordinary period of a calendar year begins after Mass is said on the Feast of the Baptism of the Lord, which falls the Sunday after the Epiphany. Thus the Mass on that day is said to be in Christmastide, but the Evening Prayers would fall in Ordinary Time.
