....declare with certainty when God's judgment will fall.

God does not announce dates for his judgments because that would take away man's free will. It is up to man when and how he is judged based on the choices he makes. God allows man the opportunity to repent, to turn away from his sins, so his judgment can be reduced, delayed, or averted.

So if a man tells you that God's judgment will fall on a specific date, you can ignore him.... and do not fear him.