https://www.usingenglish.com/forum/threads/it-may-have-been-pam-who-forgot-to-lock-the-door.300419/post-1912321
No. They all express roughly the same level of uncertainty (less than 100%). Learners often try to attach levels of possibility to these words. Don’t waste your time on it.
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https://www.usingenglish.com/forum/threads/is-could-more-sure-than-may-or-might.300288/
#3
“The difference in modality between these words is not best explained with a spectrum of certainty, in my opinion. I prefer to explain this difference as qualitative—about different kinds of possibility—rather than as quantitative by degree. In some sense, the kind of possibility we get from could is more ‘remote’ from might, but not really less ‘sure’.”
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https://dictionary.cambridge.org/grammar/british-grammar/could-may-and-might
We use could, may and might to express degrees of possibility. Many native speakers disagree on which one expresses more or less certainty.
