According the Bible, there are no signs that precede the rapture; it will happen without warning, in the twinkle of an eye. There are three different theories about the timing of the rapture: pre-tribulation, mid-tribulation and post-tribulation.
The rapture of the church is when all both dead and living Christians will rise up to heaven. The Bible states that this event will happen without warning and will take less than half an hour.
The tribulation, as described in the Bible, is the seven-year period before the return of Christ to earth. The Bible describes this period as fraught with famine, war and disease. During the tribulation, the anti-Christ will appear and create a peace covenant with Israel. Three and a half years into the tribulation, the covenant will be broken and the anti-Christ will go to war to destroy Israel.
Pre-tribulationists believe that the rapture will take place before the beginning of the seven years of tribulation. In this theory, Christians both living and dead will be taken to God and not have to endure the tribulation. The mid-tribulationists believe that the rapture will occur after three and a half years of the tribulations. This belief has the Christians leaving before the war against Israel. The post-tribulationists believe the rapture will happen at the end of the seven years of tribulations.