Hermione arguably has the best, most evolutionary hairstyles. In year one Hermione has bushy hair that sources say: young Emma Watson didn’t like the look of, well as much as we think Emma looked great it was the most look alike to the books
In year two Hermione has less bushy but sleek curls (even though it does not match the books) it made Hermione look very pretty, we also spotted her on many occasions wearing the half up half down.
By year three Hermione starts to loose the sleek curls and bushy hair to kind of be in the middle, she also looses the hairstyles.
In year four we see the absolute best hairstyles, the one that completely blew us away was her Yule ball style that most just can’t compete with. Then we see her for a very short time pigtail braids on the very side of her head. She also starts to wear ponytails too.
By years 5 & 6 Hermione starts to wear her hair down as the plots get darker. And we don’t see many new styles.
In the two last 7 movies Hermione has bushy hair but wears it in braids and ponytails, she doesn’t do anything much because as we know she is on the run from vol- you know who.

And that just about covers the best Hermione hairstyles.