Study the example below:
Sue is looking for her mother. She knows she should have arrived home, she doesn’t know where she is but she gets some suggestions from her sister.
She may be on her way home. (perhaps she is on her way home)
She might be having a drink with her friend. (perhaps she is having a drink with her friend)
Ask dad, he might know. (perhaps dad knows)
May or might is used to say that something is a possibility. The negative forms are may not and might not / mightn’t.