We use may:

when we are not sure about something in the present or future:
Jack may be coming to see us tomorrow.
(= Perhaps Jack will come to see us tomorrow.)
Oh dear! It's half past ten. We may be late for the meeting.
(= Perhaps we will be late for the meeting.)
She's had no sleep. She may be tired.
(= Perhaps she is tired.)

to ask for permission in a formal way:
May I borrow the car tomorrow?
May we come a bit later?

to give permission in a formal way:
You may go now.
You may come at eleven if you wish.

to say that someone has permission in a formal way:
Students may travel for free.

We can use may not to refuse permission or to say that someone does not have permission, but it is formal and emphatic:

You may not borrow the car until you can be more careful with it!
Students may not wear jeans.

We use might when we are not sure about something in the present or future:

I might see you tomorrow.
It looks nice, but it might be very expensive.
It's quite bright. It might not rain today.
#Using_May_&_Might_in_English --
#Explained_in_Urdu