Might is a modal auxiliary verb. It is followed by an infinitive without to. There is no –s in the third person singular.

• It might rain this evening.

Questions and negatives are made without do.

• We might not be home before evening.

Might does not have infinitives or participles. When necessary, we use other words.

Meaning

Might is used to talk about possibility, and to ask for and give permission.

Possibility

We often use might to say that there is a chance that something is happening, or that there is a possibility of it happening.

• It might rain this evening.
• She might come.

May and Might: The difference

Might is the past equivalent of may in indirect speech. But it does not normally have a past meaning. It is used in the same way as may to talk about the present or future. The difference is that might usually refers to situations that are less probable or less definite. It is used when people think that something is possible but not very likely.

• I may get a job soon. (Perhaps a 50% chance)
• I might get a job soon. (Perhaps a 30% chance)

Might can mean ‘would perhaps’.

• Don’t play with knives. You might get hurt. (= Perhaps you would get hurt.)

Might + perfect infinitive

The structure might + perfect infinitive can be used to say that it is possible that something happened or was true in the past.

• What was that noise? It might have been a cat.

The same structure can be used to say that something was possible but did not happen.

• You were stupid to try climbing up there. You might have killed yourself.

Permission

Might can be used to ask for permission. It is very polite and formal; it is not common and is mostly used in indirect questions.

• I wonder if I might borrow your car.