I walk to school, and by the time i get there my hair is frizzy :( ?

[? j???Y ?]

So I can get my hair pretty straight and flat, like i want it to be. But then i have to walk to school and by the time I get there its all frizzy and starts to curl back up. Is there any way to get my hair to not freak out? (I do try tying it up in a lose ponytail and that helps a little, but not a not.)