"The keys of the unseen are five & none knows them but Allah
Narrated Ibn Umar: The Prophet [PBUH] said, "The keys of the unseen are five & none knows them but Allah:
(1) None knows what is in the womb, but Allah;
(2) None knows what will happen tomorrow, but Allah;
(3) None knows when it will rain, but Allah;
(4) None knows where he will die, but Allah (knows that);
......(5) and none knows when the Hour will be established, but Allah."
[Bukhari, Book 9 Vol 93 Hadith 476]