It may/might have rained.

[Untaught88]

Hi,

I would like to ask three questions.
1: Are the following correct?
2: Is "may" used for something which is more likely to happen and "might" for something which is less likely?
3: Can I use "may/might have" in interrogative sentences?

It may/might have rained.
She may/might have broken the glass.

 

[emsr2d2]

As a general rule, it's safe to use "may" for permission and "might" for possibility. There is some crossover and not everyone makes the distinction (in fact, "might" used to commonly be used for permission) but you won't be wrong if you use them that way. It's nothing to do with anything being likely or less likely.

It might have rained.
She might have broken the glass.
Might she have broken the glass?
Might it have been the cat that smashed the vase?

May I go to the bathroom?
Yes, you may.

 

[GoesStation]

Either verb is possible in your sentences.

Might can indicate a condition contrary to what actually happened: I might have been a billionaire if I'd gotten to know Gates better. I tend to choose may when more than one outcome is reasonable: she may be at the beach; if not, she's probably playing tennis.

I see and hear may more and more often in sentences like the first. The distinction is fading, though I think it's useful.