Were civil marriages ever performed in The Church of Jesus Christ of Latter-day Saint temples? If so, what was the time frame? Thanks.
There is a bit of confusion here because we commonly combine two things into one. The two things are marriages and sealings. We do this when we use the term temple marriage. When we say temple marriage we mean a marriage that has been sealed, usually in the same ceremony. In the United States, The Church of Jesus Christ of Latter-day Saints strongly encourages all couples to have such a combined ceremony where possible, thus adding to this confusion. But we can see the difference clearly when we look to countries where marriages are required to be open to the public (England for example) . In those countries faithful LDS couples are married in a legal civil ceremony and then quickly move to the nearest temple to be sealed together.
Now when people think of a ‘civil’ marriage they are generally meaning a legal marriage without all the religious trappings and ceremonies. The Church obeys the laws of the land. Since all the marriages performed in the temple must obey the laws of the law, we could say that, as a minimum, all marriages performed in the temple are ‘civil’ marriages. We simply believe that the sealing builds on that and transcends the ‘civil’ service.
Now we commonly call a temple sealing a marriage for time and eternity. However the temple can also do for time only marriages. Generally this happens when two faithful members who have already been sealed, lose their spouses. If they decide they don’t wish to be alone for this life-time but they also don’t wish to cancel their sealing, they can be married (but not sealed) in the temple.
Thus to answer your question civil marriages are currently being performed in the temples (as the laws of the land permit) and have been for a very long time.
Now as the laws of the lands might change depending on the political climate around the subject of marriage, if those laws change to a point where the Church can/will not perform marriages anymore, the Church has already shown that it is willing to separate the marriage ceremony from the sealing ceremony. If that happens then the answer to your question could very well become none.