Narrated Ibn `Umar: Allah's Messenger (ﷺ) (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."
The chain is ordered from the source of the saying to the compiler: 1 = the speaker/first transmitter, the following links those who passed it on in turn, and at the bottom al-Bukhari who compiled the work. Click a narrator to list every hadith in which he appears; the number in parentheses is how many hadiths across the collections on this site the narrator appears in.