MayWe can use 'may' to ask for permission. However this is rather formal and not used very often in modern spoken EnglishMay I borrow your pen?May we think about it?May I go now?We use 'may' to suggest something is possibleIt may rain later today.I may not have time to do it today.Pete may come with usmightWe use 'might' to suggest a small possibility of something. Often we read that 'might' suggests a smaller possibility that 'may', there is in fact little difference and 'might is more usual than 'may' in spoken English.She might be at home by now but it's not sure at all.It might rain this afternoon.I might not have time to go to the shops for you.I might not go.For the past, we use 'might have'.He might have tried to call while I was out.I might have dropped it in the street.