I will throw in with Ken. If heat got to our radio control equipment all of South Mississippi would have to replace equipment every six months. I do think temperature swings might cause some harm. Heat has never bothered my planes as much as landing two inches to low. I do think this is a great subject for discussion. We can all learn something worth while about storing these things and stuff required to fly and maintain them.
One of the major reasons I enjoy the beginners forum is I get to learn. Perhaps we will learn from others on this subject of storing our equipment.