Straightening really curly hair in thick humidity!?

I live in Louisiana and the humidity down here is dreadful!!! Does anyone know a straightening product that helps keep hair straight even when its very humid outside?? I have very tight curls and shoulder blade length hair so I have a lot of hair and even in the spring it doesn't stay really straight. Even if you know of a really good hair straightening product, but you aren't sure if it would work well here...do tell anyways (: As of now I am using a Chi heat guard and a Redken heat glide. I realize an easy solution would be to chemically straighten my hair..but id rather not unless there is no other option. Thank you!