You WON'T know the day! (and if someone says that they do know the day ask them about these verses)

Mark 13:32
But of that day or hour no one knows, not even the angels in heaven, nor the Son, but the Father alone.

Luke 12:46
the master of that slave will come on a day when he does not expect him and at an hour he does not know, and will cut him in pieces, and assign him a place with the unbelievers.

John 16:25
These things I have spoken to you in figurative language; an hour is coming when I will no longer speak to you in figurative language, but will tell you plainly of the Father.

Revelation 3:3
So remember what you have received and heard; and keep it, and repent. Therefore if you do not wake up, I will come like a thief, and you will not know at what hour I will come to you.

We are in the last hour, and have been for a long time:

I John 2:18
Children, it is the last hour; and just as you heard that antichrist is coming, even now many antichrists have appeared; from this we know that it is the last hour.

Revelation 14:7
and he said with a loud voice, "Fear God, and give Him glory, because the hour of His judgment has come; worship Him who made the heaven and the earth and sea and springs of waters.

But you will Recognize the very end times:

Mark 13:8
For nation will rise up against nation, and kingdom against kingdom; there will be earthquakes in various places; there will also be famines. These things are merely the beginning of birth pangs.

I Thessalonians 5:1-3
1 NOW as to the times and the epochs, brethren, you have no need of anything to be written to you. 2 For you yourselves know full well that the day of the Lord will come just like a thief in the night. 3 While they are saying, "Peace and safety!" then destruction will come upon them suddenly like labor pains upon a woman with child, and they will not escape.

II Thessalonians 2:1-2
1 Now we request you, brethren, with regard to the coming of our Lord Jesus Christ, and our gathering together to Him, 2 that you may not be quickly shaken from your composure or be disturbed either by a spirit or a message or a letter as if from us, to the effect that the day of the Lord has come.

Be ready:

Luke 21:36
36 "But keep on the alert at all times, praying in order that you may have strength to escape all these things that are about to take place, and to stand before the Son of Man."

In Depth:

Matt 24:1-31
1 And Jesus came out from the temple and was going away when His disciples came up to point out the temple buildings to Him. 2 And He answered and said to them, "Do you not see all these things? Truly I say to you, not one stone here shall be left upon another, which will not be torn down." 3 And as He was sitting on the Mount of Olives, the disciples came to Him privately, saying, "Tell us, when will these things be, and what will be the sign of Your coming, and of the end of the age?" 4 And Jesus answered and said to them, "See to it that no one misleads you. 5 "For many will come in My name, saying, 'I am the Christ,' and will mislead many. 6 "And you will be hearing of wars and rumors of wars; see that you are not frightened, for those things must take place, but that is not yet the end. 7 "For nation will rise against nation, and kingdom against kingdom, and in various places there will be famines and earthquakes. 8 "But all these things are merely the beginning of birth pangs. 9 "Then they will deliver you to tribulation, and will kill you, and you will be hated by all nations on account of My name. 10 "And at that time many will fall away and will deliver up one another and hate one another. 11 "And many false prophets will arise, and will mislead many. 12 "And because lawlessness is increased, most people's love will grow cold. 13 "But the one who endures to the end, he shall be saved. 14 "And this gospel of the kingdom shall be preached in the whole world for a witness to all the nations, and then the end shall come. 15 "Therefore when you see the abomination of desolation which was spoken of through Daniel the prophet, standing in the holy place (let the reader understand), 16 then let those who are in Judea flee to the mountains; 17 let him who is on the housetop not go down to get the things out that are in his house; 18 and let him who is in the field not turn back to get his cloak. 19 "But woe to those who are with child and to those who nurse babes in those days! 20 "But pray that your flight may not be in the winter, or on a Sabbath; 21 for then there will be a great tribulation, such as has not occurred since the beginning of the world until now, nor ever shall. 22 "And unless those days had been cut short, no life would have been saved; but for the sake of the elect those days shall be cut short. 23 "Then if anyone says to you, 'Behold, here is the Christ,' or 'There He is,' do not believe him. 24 "For false Christs and false prophets will arise and will show great signs and wonders, so as to mislead, if possible, even the elect. 25 "Behold, I have told you in advance. 26 "If therefore they say to you, 'Behold, He is in the wilderness,' do not go forth, or, 'Behold, He is in the inner rooms,' do not believe them. 27 "For just as the lightning comes from the east, and flashes even to the west, so shall the coming of the Son of Man be. 28 "Wherever the corpse is, there the vultures will gather. 29 "But immediately after the tribulation of those days the sun will be darkened, and the moon will not give its light, and the stars will fall from the sky, and the powers of the heavens will be shaken, 30 and then the sign of the Son of Man will appear in the sky, and then all the tribes of the earth will mourn, and they will see the Son of Man coming on the clouds of the sky with power and great glory. 31 "And He will send forth His angels with a great trumpet and they will gather together His elect from the four winds, from one end of the sky to the other.

Matthew 24:44,50
44 "For this reason you also must be ready; for the Son of Man is coming at an hour when you do not think He will. 50 the master of that slave will come on a day when he does not expect him and at an hour which he does not know,

I Thessalonians 5:1-11
1 NOW as to the times and the epochs, brethren, you have no need of anything to be written to you. 2 For you yourselves know full well that the day of the Lord will come just like a thief in the night. 3 While they are saying, "Peace and safety!" then destruction will come upon them suddenly like labor pains upon a woman with child, and they will not escape. 4 But you, brethren, are not in darkness, that the day would overtake you like a thief; 5 for you are all sons of light and sons of day. We are not of night nor of darkness; 6 so then let us not sleep as others do, but let us be alert and sober. 7 For those who sleep do their sleeping at night, and those who get drunk get drunk at night. 8 But since we are of the day, let us be sober, having put on the breastplate of faith and love, and as a helmet, the hope of salvation. 9 For God has not destined us for wrath, but for obtaining salvation through our Lord Jesus Christ, 10 who died for us, so that whether we are awake or asleep, we will live together with Him. 11 Therefore encourage one another and build up one another, just as you also are doing.

II Thessalonians 2:1-17
1 NOW we request you, brethren, with regard to the coming of our Lord Jesus Christ and our gathering together to Him, 2 that you not be quickly shaken from your composure or be disturbed either by a spirit or a message or a letter as if from us, to the effect that the day of the Lord has come. 3 Let no one in any way deceive you, for it will not come unless the apostasy comes first, and the man of lawlessness is revealed, the son of destruction, 4 who opposes and exalts himself above every so-called god or object of worship, so that he takes his seat in the temple of God, displaying himself as being God. 5 Do you not remember that while I was still with you, I was telling you these things? 6 And you know what restrains him now, so that in his time he will be revealed. 7 For the mystery of lawlessness is already at work; only he who now restrains will do so until he is taken out of the way. 8 Then that lawless one will be revealed whom the Lord will slay with the breath of His mouth and bring to an end by the appearance of His coming; 9 that is, the one whose coming is in accord with the activity of Satan, with all power and signs and false wonders, 10 and with all the deception of wickedness for those who perish, because they did not receive the love of the truth so as to be saved. 11 For this reason God will send upon them a deluding influence so that they will believe what is false, 12 in order that they all may be judged who did not believe the truth, but took pleasure in wickedness. 13 But we should always give thanks to God for you, brethren beloved by the Lord, because God has chosen you from the beginning for salvation through sanctification by the Spirit and faith in the truth. 14 It was for this He called you through our gospel, that you may gain the glory of our Lord Jesus Christ. 15 So then, brethren, stand firm and hold to the traditions which you were taught, whether by word of mouth or by letter from us. 16 Now may our Lord Jesus Christ Himself and God our Father, who has loved us and given us eternal comfort and good hope by grace, 17 comfort and strengthen your hearts in every good work and word.

Revelation 11:7-14
7 When they have finished their testimony, the beast that comes up out of the abyss will make war with them, and overcome them and kill them. 8 And their dead bodies will lie in the street of the great city which mystically is called Sodom and Egypt, where also their Lord was crucified. 9 Those from the peoples and tribes and tongues and nations will look at their dead bodies for three and a half days, and will not permit their dead bodies to be laid in a tomb. 10 And those who dwell on the earth will rejoice over them and celebrate; and they will send gifts to one another, because these two prophets tormented those who dwell on the earth. 11 But after the three and a half days, the breath of life from God came into them, and they stood on their feet; and great fear fell upon those who were watching them. 12 And they heard a loud voice from heaven saying to them, "Come up here." Then they went up into heaven in the cloud, and their enemies watched them. 13 And in that hour there was a great earthquake, and a tenth of the city fell; seven thousand people were killed in the earthquake, and the rest were terrified and gave glory to the God of heaven. 14 The second woe is past; behold, the third woe is coming quickly.