This is a question that I believe has been on the minds of many Christains for ages. When you read the writings of Paul and John and Peter and possibly many others, you can glean a sense of imminence of the coming of Christ embeded in their comments. However, non of them ventured to predict the timing of the coming of Christ. Infact, my sense is that as much as they may have anticipated it in their life time, they generally echoed the sense of futility of trying to guesstimate the time of the event that Jesus himself expressed.
In the gospel of Matthew 24:36, Jesus responded in an elaborate way on this subject to indicate
(a) No one (not even him--Jesus Christ) knows, except God the father alone.
(b) That the event is designed to come as a surprise which reinforces the need to be ready always.
Also, in Luke 12:39, his response followed thesame trajectory by not only saying that it was futile to sit around trying to predict the time but also that it is designed to come as a surprise.
Examples from the two previous experiences ( the destruction of Sodom & Gomorrah and the story of Noah) corroborate this sense of unpredictability because these events actually came as a surprise to the people involved.
Why then are some people trying to suggest that somehow, they know when Christ is coming back?