Many have guessed, but nobody has been correct. Just make sure you are ready at ALL times.
Matthew 24:30-36English Standard Version (ESV)
30 Then will appear in heaven the sign of the Son of Man, and then all the tribes of the earth will mourn, and they will see the Son of Man coming on the clouds of heaven with power and great glory. 31 And he will send out his angels with a loud trumpet call, and they will gather his elect from the four winds, from one end of heaven to the other.
32 “From the fig tree learn its lesson: as soon as its branch becomes tender and puts out its leaves, you know that summer is near. 33 So also, when you see all these things, you know that he is near, at the very gates. 34 Truly, I say to you, this generation will not pass away until all these things take place. 35 Heaven and earth will pass away, but my words will not pass away.
36 “But concerning that day and hour no one knows, not even the angels of heaven, nor the Son,[a] but the Father only.