The usages of may and might are similar. Although one or the other is more likely to be used in some contexts, neither choice will be wrong. Below is an introduction to the most important uses of may and might.
1. May and might are both commonly used to talk about possibility:
You may have a little difficulty driving at night.
I might have an allergy to wheat.
We may go to London for vacation, if we can still afford it.
Note that many grammar books say it is better to use might when something is less likely, and may when something is more likely, but this is a flexible rule.
2. In talking about the past, may have and might have are both common:
The homework might have been too difficult for them.
I may have been sleeping when you called.
Looking back, there might have been some signs of trouble, but we didn’t see them.
3. Might have is more common for statements about things that could have happened but didn’t (counterfactuals), but may have is sometimes used:
If they had lived in another time, their lives might have been different,
I might have gone to school there, but because I didn’t have enough money, I started working instead.
If he had shown reliability from the start, things may have been different. "
4. May is used to ask permission in formal speech, and both may and might are used to make polite suggestions:
May I be excused?
May I help you with your luggage?
Next time you might try washing it in the sink.
You may want to consider leaving early