Storing firearms in hot closet?

I bought a dehumidifier for my closet which keeps the room at a low humidity. However, combined with the summer heat, the dehumidifier makes the temperature 90 degrees Farenheit. I've heard that as long as the humidity is low and the temperature remains relatively constant, the guns, when oiled properly should be fine. So is it alright to leave my rifle and shotgun in such a hot room?