Here are just a few Scriptural proofs of the Rapture occurring before the Tribulation:
1. The exhortation to be comforted by the "coming of the Lord" (1Thes 4:18) is valid only in the context of the pre-trib view. It could even be a fearsome thing in a post-trib view.
2. We are exhorted to look for the "Glorious Appearing of our Lord and Savior Jesus Christ." (Titus 2:13) If there are any prophetic events (ie: tribulation) to come first, then this passage is nonsensical
3. Again, we are to "purify ourselves" in view of his coming.(1 John 3:2-3) If his coming is not imminent then the passage is meaningless.
4.. The church told *only* to look for the Coming of Christ. It is Israel and the tribulation saints that are told to look for signs.
5. The translation of the church is never mentioned in any context dealing with the second coming of Christ at the end of the Tribulation.
6. The church is "not appointed to wrath" (Rom 5:9; 1 Thes 1:9-10) The church cannot enter into the "great day of their wrath."
7. The Church will not be "overtaken by the Day of the Lord." (1 Thes 5:1-9) (Day of the Lord is another term for the great tribulation.)
8. The church will be "kept from the hour of testing that shall come upon all the world." (Rev. 3:10)
9. The believer will escape the tribulation (Luke 21:36).
10. It is in the character of God to deliver His own from the greatest times of trial. (Lot, Rahab. Israel, Noah, etc)
11. It is clear that there is a time interval between the translation of the church and the Return of Christ. (John 14:3)
12. The godly remnant of the tribulation has the attributes seen in OT Israel and not the church. The church is not present in the prophecies of Revelation.
13. The pre-trib view, unlike the post-trib view, does not confuse terms like elect and saints which apply to believers of all ages, as opposed to terms like church and in Christ, which apply only to those who are the body of Christ in this age.
14. The Holy Spirit is the Restrainer of evil in the world. He cannot be taken out as prophesied unless the church which is indwelt by the Holy Spirit is taken out. (2 Thessalonians 2:1-8)
15. The Holy Spirit will be taken out before the "lawless one" is revealed. That lawless one will certainly be revealed in the tribulation. In fact, the tribulation begins with the signing of the covenant between that lawless one and Israel. That act will reveal him.
16.. The "falling away" in 2 Thes 2:3 would better be understood in its context as "the departure." This is a reference to the departure of the Holy Spirit as He indwells the church.
17. Only the pre-trib view allows for a truly literal interpretation in all of the OT & NT passages regarding the great tribulation. 18.. Only the pre-trib position clearly distinguishes the church and Israel and God's dealing with each. The Necessity of an interval of time between the Rapture and the Second Coming.
19. All believers must appear before the Judgment Seat of Christ (2 Cor 5:10). This event is never mentioned in the account of events surrounding the second coming.
20. The "four and twenty elders" in Rev. 4:1-5:14 are representative of the church. Therefore it is necessary that the church, undivided, be brought to glory before those events of the tribulation.
21. There is clearly a coming of Christ for his bride before the second coming to earth. (Rev 19:7-10).
22. Tribulation saints are not translated at the second coming of Christ but carry on ordinary activities. These specifically include farming, construction, and giving birth. (Is 65:20-25).
23. The Judgment of the Gentile nations following the second coming (Mat 25:31-46) indicates that both the saved and the lost are in a natural body which would be impossible if the translation had taken place at the second coming.
24. If the translation took place at the same time as the second coming, there would be no need to separating the sheep from the goats at the subsequent judgment. The act of the translation would be the separation.
25. The Judgment of Israel (Ez 20:34-38) occurs after the second coming and requires a regathered Israel. Again, the separation of the saved and the lost would be unnecessary if all the saved had previously been separated by a translation at the second coming.
26. At the Rapture, the church meets Christ in the air. At the second coming, Christ returns to the Mt of Olives.
27. At the time of the Rapture, the Mt of Olives is unchanged. At the second coming it is divided forming a valley east of Jerusalem.
28. At the time of the Rapture, saints are translated. No saints are translated at the time of the second coming.
29. At the time of the Rapture, the world is not judge for sin, but descends deeper into sin. At the second coming, the world is Judged by the King of kings.
30. The translation of the church is pictured as a deliverance from the day of wrath, whereas the coming of Christ is a deliverance for those who have suffered under severe tribulation.
31. The Rapture is immanent whereas there are specific signs which precede the second coming.
32. The translation of living believers is a truth revealed only in the NT. The second coming with the events surrounding it is prominent in both OT and NT.
33. The Rapture is only for the saved, while the tribulation and second coming deals with the entire world.
34. No unfulfilled prophecy stands between the church and the Rapture. Many signs must be fulfilled before the second coming of Christ.
35.. No passage in either OT or NT deals with the resurrection of the saints at the second coming nor mentions the translation of living saints at that same time.
36. Only the pre-trib view maintains the distinction between the "great tribulation" and the tribulations in general which we all experience.
37. . The great tribulation is properly understood in the pre-trib view as a preparation for the restoration of Israel. (Deut 4:29-30. Jer 30:4-11, Dan 9:24-27, Dan 12:1-2)
38.. Not one single passage in the OT which discusses the tribulation, mentions the church.
39.. Not one single passage in the NT which discusses the tribulation, mentions the church.
40. There is no proper groundwork provided that the 7th trumpet of Rev is the last trumpet of 1 Cor 15. It is accepted only on the basis of assumption. The pre-trib view maintains the proper distinction between the prophetic trumpets of the church and the trumpets of the tribulation.
41. The Unity of Daniel's 70th week is maintained by the pre-trib view. By contrast, the mid-trib view destroys the unity and confuses the program for Israel and the church. The post trib view usually denies the clear teaching of the 70th weeks by subverting it into some form or another of allegory.
42. The gathering of saints after the tribulation is done by angels whereas the gathering of the church is done by "The Lord Himself."
I'll await the Scriptural validation for your belief about when the Rapture happens.