Sahih Bukhari | Volume 6 | Hadith Number 219

Narrated by Ibn Umar
Allah's Apostle said, "The keys of Unseen are five which none knows but Allah: None knows what will happen tomorrow but Allah; none knows what is in the wombs (a male child or a female) but Allah; none knows when it will rain but Allah; none knows at what place one will die; none knows when the Hour will be established but Allah." (See The Qur'an 31:34.")