Guitar care question

I'm heading out to Oklahoma this weekend, and won't be taking my guitar. It's summer time and we don't have air conditioning (other than window units) so it gets pretty hot in my home.

I'm taking the case because someone is giving us a guitar when we get down there.

How do I need to store this thing so it doesn't get all warped and damaged?

It's a solid Spruce top with Maple back/sides. I'm thinking of putting it in an interior closet with the coats etc. that way it's got no walls to the outside.

Any help would be much appreciated!!

Thanks!