Or the other explanation would be that they believe that they had a premonition but only vaguely connected some loose thoughts or dreams after an event that coincidently are related. Indeed, I'd go so far as to say that people experience premonitions every day, but they're only noticed if an event happens that coincidentally resembles the thoughts or dreams.
"I had this feeling something was going to happen," seems to be the going premonition. Hell, something always happens.