May and might are modal auxiliary verbs. We use them to talk about possibility.

Grammar

After may and might we use infinitives without to.

He may accept the offer. (NOT He may to accept the offer.)

May and might do not take the –s marking when the subject is a singular pronoun.

She may come. (NOT She mays come.)
He might recognize you. (NOT He mights recognize you.)
I may accept the offer.

Questions and negatives are made without do.

May I help you? (NOT Do I may help you?)
He may not come. (NOT He doesn’t may come.)

May and might do not have infinitive or participle forms. For example, forms like maying, mighting, to may etc. do not exist.

Uses

May and might are mainly used to talk about possibility – the chances of something happening. In a formal style, we also use them to ask for and give permission.

Possibility

We often use may and might to say that there is a possibility of something happening.

He may pass the test.
It may rain in the evening.
He may come.
We may take a vacation at the end of this month.
I may visit my grandparents next week.
Gautam might phone.
They might accept the invitation.
She might get the job.
You may be right.

Notes

Might does not normally have a past meaning. The difference between may and might is that might shows less possibility than may.

Our team may win. (Perhaps a 50% chance)
Our team might win. (Perhaps a 20% chance)

Questions

We do not normally use may in direct questions about probability. Can is possible in this case.

Where is Gauri? Can she have gone shopping? OR Do you think Gauri has gone shopping? (BUT NOT May she have gone shopping?)