Yes it is true that no man knows the date nor hour that He is going to return .. But God loves us so much He even told us to look out for signs of His return.
"Now learn a parable of the fig tree; When his branch is yet tender, and putteth forth leaves, ye know that summer is nigh: So likewise ye, when ye shall see all these things, know that it is near, even at the doors." (Matthew 24:32-33 KJV)
He tells us here when these things begin to happen, His return is soon to come. (Read the whole chapter to see what these things are)
In 2 Timothy 3:1-5, Paul said, "This know also, that in the last days perilous times shall come. For men shall be lovers of their own selves, covetous, boasters, proud, blasphemers, disobedient to parents, unthankful, unholy, Without natural affection, trucebreakers, false accusers, incontinent, fierce, despisers of those that are good, Traitors, heady, highminded, lovers of pleasures more than lovers of God; Having a form of godliness, but denying the power thereof: from such turn away."
And another good one is in the book of Acts.
"And it shall come to pass in the last days, saith God, I will pour out of my Spirit upon all flesh: and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams: And on my servants and on my handmaidens I will pour out in those days of my Spirit; and they shall prophesy: And I will shew wonders in heaven above, and signs in the earth beneath; blood, and fire, and vapour of smoke: The sun shall be turned into darkness, and the moon into blood, before that great and notable day of the Lord come:" (Acts 2:17-20 KJV)
We had a blood moon last year. I believe we have two more this year. We also have a solar eclipse which is the darkened sun.