One of the factors for wax to deteriorate is temperature. Will the car be in a garage that's temperature controlled? If it's a nice and cool garage, then I don't think it would be a problem. The reason why I mention temperature is because I experienced this firsthand. I prepped and waxed my new vehicle and kept it in in my garage. It's not my daily driver so it barely sees the sun, perhaps once every two weeks. Anyhow, everytime I would pass through the garage, I would run my hand through the side of the car to feel its slickness. Towards the end of two weeks or so, I could tell a difference. It was not as slick as when I first applied my LSP. Again, it was pretty warm several of those days so the side of the car started to feel more grippy and less slick.
I think humidity will also play a factor in storing a vehicle with wax. Haven't had to deal with too much humidity in my neck of the woods, so I can't write about it too much.
Also, will the car be under a car cover when it's stored?
-Mike