Temples are not regular places of Sunday worship for members of The Church of Jesus Christ of Latter-day Saints. They are quite different from the thousands of regular chapels or meetinghouses all over the world that are used for Sunday services.
Anyone, regardless of religion, may enter a Latter-day Saint meetinghouse and attend services. However, because of the sacredness of temples as “houses of the Lord,” only members of the Church, who are in good standing are allowed to enter the temples. A member must be observing the basic principles of the faith and attest to that fact to his or her local leaders once every two years in order to enter a temple.