What's the difference?

Could someone explain me the difference between "probably", "perhaps" and "maybe" and when we use each of these words?

"Perhaps" and "maybe" both mean "possibly".  "It may rain today" and "Perhaps it will rain today" mean the same thing.  However, we don't know if the chances are 10%, 30%, 50%, 80%, etc.

"Probably" tells you that the odds (chances) that something will happen is more than 50%.  In othe words, it is more likely that something will happen than it won't happen.