Part of the ongoing Verse Quick Reference project.
Mar 13:32 “But of that day and hour no one knows, not even the angels in heaven, nor the Son, but only the Father.
In Mark 13:32, there is an unequivocal statement by Jesus about lacking some information about the future. Jesus states the “Son” does not know the day and hour of the Day of the Lord. What this verse shows is that Jesus was not omniscient of future events.
What this primarily shows is that omniscience of future events is not a requirement for divinity. This is in opposition to many classical claims about the attribute of God.
What this also shows is how generalizations and contextual understandings work within the bounds of language. Jesus is said elsewhere to “know all things” (Joh 21:17) and be the same “yesterday, today, and forever” (Heb 13:8). The knowing all things is likely only a claim that Jesus has a lot of knowledge. The being the same “yesterday, today and forever” is likely about Jesus’ moral character, in context, Jesus’ steadfast presence.
Additionally, when people point to prophecies of Jesus which did come true, they then are saying a non-omniscient being can make correct predictions of future events. This undermines any case that one has to be omniscient to accurately predict the future. Of course, in these incidents, a critic can claim that Jesus gained his information from the father, but this is assumed onto the text.
God is Open 
The classic view says that Jesus was limited as a man on earth during the incarnation and veiling of His omni attributes. He would know the hour before and after the incarnation.
My new Open Theist understanding is that the hour of the Second Coming was not fixed/set in the first century and was open to various contingencies, including the indeterminate church age (this would also fit Enyart/The Plot/Mid Acts disp, I think). When the Father knows and decides, the Son will know. It is still true that Jesus grew in knowledge as a man and would not know things on earth with His human brain that He knew pre-existence/post-resurrection.
Theologians want their cake and to eat it too. We do not have really any support for Jesus having latent attributes. Paul says that Jesus “emptied himself”, which we would assume is divesting himself of those attributes.
Php 2:6 who, though he was in the form of God, did not count equality with God a thing to be grasped,
Php 2:7 but emptied himself, by taking the form of a servant, being born in the likeness of men.
Php 2:8 And being found in human form, he humbled himself by becoming obedient to the point of death, even death on a cross.
This would still mean that a non-omniscient being can be divine. Recall, the claim is that if God has ignorance in any fashion or any way, then He is not omniscient. His knowledge cannot increase or decrease. The incarnation is the death knell to Classical Theology.
If He emptied Himself of attributes, would this not compromise His Deity just as saying He could not be tired or hungry would compromise His humanity. He is one person with two natures, but we only speculate how these two natures relate in one person on earth. I think veiling is closer than losing. At the Transfiguration, His glory was seen shining through. Omniscience, omnipotence, omnipresence is part of being eternal Deity. The incarnation is a unique thing. The issue with Open Theism is not proving that a divine being does not have to be omniscient. It is rightly defining omniscience as the knowable with the contingent future being inherently unknowable exhaustively. I agree that the incarnation is an argument against strong immutability, but I am not sure that Christ’s ignorance as human (Lk. 2:52) should be used as an argument that God is not omniscient (He is, even by Open Theism standards). A more critical philosopher may be able to prove or disprove technically. I am just musing as an amateur intuitively.