Quote from JustinC: "How do you store it to survive the temperature extremes of hot car in summer/waaaay below freezing in winter?"
The only way I have figured out how to keep my emergency stuff in the car from getting too hot or cold is to cover it with thick padding. I tried a cooler, but it still got too hot. So now I cover it with thick padding like a wool blanket, foam pad (folded twice/4 layers) and anything else in the car that can keep the heat from penetrating in to it. The items I most worry about getting hot are - food, water, meds, butane canisters for the camp stove, and sensitive first aid supplies. I check it often on hot days. Like yesterday it was in the low 100's, so I checked it several times and it was still cool.
Some of the water I keep in the car has a 5 year shelf life and can take hot temperatures. I also cover it with padding. So you might consider that if you haven't already:
http://www.nitro-pak.com/product_info.php?products_id=383I am not sure what to do about keeping your water & food from freezing. I don't have that problem here. But I imagine if you wrap it up completely with enough thick padding it might work. Maybe someone here knows of a good insulating material (that would be safe around food) that would keep your stuff from freezing.
Joy