[BobC]

I'm not an expert either, but I think the heat alone is not the worst factor. If you're talking 85-90 degrees, as opposed to 70-75 degrees, is that 20-25 degrees difference really that radical and going to have that big of an effect on the cards in the short term? Of more concern, I believe, is if the heat is directly related to being in sunlight, as the UV rays can easily and quickly do damage to a card's image. Just think back to what cards look like that had been sitting out on a table at an outside flea market. Or of even more concern I think is the heat, in conjunction with moisture. At the end of the day, I believe moisture is a bigger issue when it comes to paper and cardboard, especially in the presence of heat. Vegas is more of a dry heat, isn't it? Paper/cardboard loses its compression and rigidity in the presence of more heat. Leon's suggestion is great though, just grab a cooler. LOL