How do you manage your curly hair during the rainy season?

I don't have completely curly hair; it's wavy. My hair volume is fine, but the strands are really thin and fine.

My perm doesn't hold waves well, so I get a straightening perm twice a year and style it with a straightening iron before going out.

However, on humid days... especially during the rainy season, neither a perm nor a straightening iron works. I had an important appointment, so I went out after getting my hair carefully blow-dried at the salon, but as soon as I get hit by the humid wind, my flyaway hairs become unbelievable, like a lion's mane.

Now that the rainy season is approaching, I'm starting to get worried. How do you manage your curly hair?