Since Jesus said we can know when He returns "right at the door" (Matt. 24.33) then how do we figure out when He returns?
Very simply He returns on the 2,520th day (end of Daniel's final seven) from when the Tribulation starts. 2,520 is the smallest number divisible by all numbers from 2 to 10 as a basic prophetic working unit, and it is 7 years x 360 days per year.
Since the last 3 feasts pertain to when Jesus returns, Feast of Trumpets (representing the first rapture according to readiness, Luke 21.36, Rev. 3.10 at 9.7 "before the throne") commences the 7 year Tribulation and the 2,520th day must land on Tisha B'Av, the day the 1st and 2nd Temples were destroyed, for Jesus returns to reign in the 3rd Temple for 1000 years on earth with His overcomers. Not all who are saved receive this reward, though all saved do get to enter the New City after the 1000 years. Consider this consequences for slothful Christians.
Furthermore we know the "branch is tender" (Matt. 24.32) because Israel is a nation again and the Total Lunar Tetrads coincide with when Israel became a nation May 14, 1948 and entered Jerusalem June 7, 1967 as the signs in the heavens. The 8th feast Tetrad since Christ is 2014/15. And there are exactly 2,520 days from Sept. 14 Feast of Trumpets 2015 to Aug. 7 Tisha B'Av 2022. Not so for 2014-22 or 2016-23.
To further seal the deal, not that we need more proof, the 3 events that occur right before the Tribulation starts (Rev. 6.12) in exact order are the great earthquake (either 320,000 killed in Haiti 2010 or 5th greatest magnitude Japan 2011), the black sackcloth sun Nov. 3, 2013 (rarest of all the 4th H3 Hybrid since Christ), and of course the Total Lunar Tetrad 2014/15 that only falls on passover and tabernacles and won't happen again till 2582/83.
If you care to include other evidences like the Malachy Prophecy (Rome destroyed in the 1st half of the Tribulation in Rev. 8 in agreement with 17.16) and the prophecy of Jubilees and Ezekiel's prophecy that takes us to exactly May, 1948 when Israel would become a nation again this only strengthens the timeline. Considering the last drop of conventional oil is 2035 at 100 million barrels a day 900 billion is used up (current estimate of available oil by industry reports), any war that occurs will occur a good 15 years before that to control the flow of oil in the middle east. Hence, 200 million military units in the middle east (Rev. 9.16) and the nuclear exchange (v.18).
Now that you know this what do you do? "Overcometh" so that you become a spiritual Christian and not a carnal one to receive your reward to return with Christ to reign 1000 years. Many Christians don't care for this reward so they will lose this blessing (Rev. 1.3).