I honestly don't believe that exacty times, days, etc are given because to do so would rob us of our freewill to respond appropriately to what 'might' occur if we don't change. Fatalism would take hold and once a prophet was proved so accurate then folk would say "it's foretold...it's GOTTA be what happens". I don't see that as the function of prediction........it's more like "this and that will unfold" and the particulars are for us to take hold of and address as they happen according to our need for spiritual growth at the time