Sahih Bukhari Volume 2, Book 17, Hadith Number 149

Narated By Ibn ‘Umar : Allah’s Apostle (p.b.u.h) said, “Keys of the unseen knowledge are five which nobody knows but Allah… nobody knows what will happen tomorrow; nobody knows what is in the womb; nobody knows what he will gain tomorrow; nobody knows at what place he will die; and nobody knows when it will rain.”