God tells us the exact time. Scholars have debated and surmised but we know. It is right at the 3.5 year mark of the last 7 years.
How do we know? Ezekiel 39:22 tells us. Here, the Magog war is described in detail in chapter 38. Then God says as a result of this war, Israel will know who God is and will forever, from that point. Read it.
Now how do we know this is in the middle of the last 7 years? God says so. Israel is unblinded as a nation when the first Beast reveals who he really is. This is what unblinds them and they see Jesus and follow Him.
Well, he reveals who he is midway into the last 7 years…at the 3.5 year mark.
The rapture also happens when Israel is unblinded. Paul tells us in Romans 11. When the fullness of the gentiles has come in (the church is gathered) Israel is unblinded.
So these 3 major events happen at the same time…the rapture, the unblinding of nation Israel and the Magog war. All of this is right at the 3.5 year mark. Glory to God!