In fact, while all the "votes" may go in at different times, the electors do all cast their vote at the same time. The Monday after the second Wednesday in December. Because we have the electoral college system and not a popular vote system we, our states, choose electors to "vote" for us. However, while electors have always given their electoral points to whatever candidate won the state, they have the option not to. This is one of the many good reasons to remove our current electoral college system because it could, essentially, void your vote if an elector really wanted to. Also, the media can "guess" at who won all they want, it doesn't mean it is fact until the electoral votes are in in December. However, because we can see the results of the popular vote, we can usually get a good idea who won way before the electors cast their votes.