Glad you brought that up. I always like to remind people that the verse you quoted has the verb in the PERFECT Tense and that there is nothing it it that says we can never know. In fact if is said that only the Father could know, then it would mean that even God our Father is limited or would break the very verse you stated if He were to let even His and our Lord Jesus Christ know. People don't seem to realize that when they quote it.
The meaning of the verse is that Only the Father knows the day and hour. Therefore, anyone that knows the day and hour means that they were revealed it by the Father. In if you go to ACTS chapter 1 they inquire with Christ as follows:
Act 1:4 And, being assembled together with them, commanded them that they should not depart from Jerusalem, but wait for the promise of the Father, which, saith he, ye have heard of me.
Act 1:5 For John truly baptized with water; but ye shall be baptized with the Holy Ghost not many days hence.
The Ascension
Act 1:6 When they therefore were come together, they asked of him, saying, Lord, wilt thou at this time restore again the kingdom to Israel?
Act 1:7 And he said unto them, It is not for you to know the times or the seasons, which the Father hath put in his own power.
Act 1:8 But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth.
Now did you notice it? That first use of "POWER:" there means "Authority". So they couldn't know what was put under the Authority of the Father. Why? - because they hadn't receive HIS Spirit which is the Holy Spirit by which they cry ABBA meaning Father.