I'm looking for a laptop sleeve that isn't waterproof, but is resistant to the humidity in the air. It gets kinda humid in my house in the summer and I don't want my computer to get all wet inside.
I'd be surprised if normal room humidity would cause a notebook to get wet inside, especially with the heat they generate while running. The humidity where I am is routinely 90%+ (far more average humidity than where you are) and I've never had a problem with it. If you want to be extra careful, though, you could simply add a humidity packet, such as Zorb-It to your existing case.