We use the modal verbs may and might to talk about possible activities or happenings in the future.
There isn't much difference between the two. So you can say:
Sentences formed with might are less likely to happen than those with may. For example:
Of course, these figures may vary depending on the situation.
However, when the situation is unreal, only might can be used:
If you want to emphasise progression of a situation, you may use the continuous form of the verb after the modal:
If you're using the reported speech, may becomes might: