May and might are both used to talk about possibility.
- It may rain this evening.
- She may come later.
- We might go tomorrow.
Might can often suggest a more uncertain possibility.
May is also commonly used to ask for or give permission.
- May I come in?
- You may leave now.
Simple guide
For possibility, both words are often possible. Might can sound more tentative, while may is also commonly used for permission.