Prediction literally means "spoken and/or written beforehand" so one of differences between the two is the former is in a shareable format, and the latter is thought that could, but doesn't have to be shared. Of course once it is shared and then subsequently occurs, it becomes a prediction and not just personal knowledge.

Another difference is that a successful prediction can manifest through a fluke, coincidence, probability of less than 1, or hindsight editing of claim, whereas "knowing" is a probability of 1.