We run temps here in the tropics of 110 with humidity, winter never gets below 50, unless something is in the refrigerator, its usually in heat a 270 days a year. That said I am not sure how hot an attic is, we dont have them in our houses as they are more flatroofed. If attics are directly under non insulated roof iron(?) that may get a lot hotter than what I am referring to..
Just talking general storage areas, like a barn or non AC room or garage, we store our preps for cyclones(hurricanes) and floods each year. Not for any sort of major destruction, just for the 1-2 weeks major highways can get cut off by water and we have to be semi reliant.
Generally all foodstuffs I find last their expected lifetime in the heat . I have 2 year old rice in an old army trunk and a range of other products like lentils, chickpeas, powdered milk, pasta etc. I seal things very well but dont go as far as mylar, just plastic bags inside cliplock lunchboxes. It does fine.
Mould growing on items is the biggest concern here, and to be honest textiles, camping equipment, leather goods, etc tend to fair less well than foodstuffs. The idea is to make sure its dry getting packed (I often pack my stores in AC to get the humidity down before it goes into the storage area) I pack items separately from other items in bags as much as possible(so if one item developes the dreaded green fuzz it does not contaminate everything else next to it) add dessicant/absorbent material( I usually order this directly from a chemical company, the real stuff works a lot better than rice, kitty litter and other home ideas. I put a small amount in a ladies footstocking in each bag) and then I carry out inspections every few months, and air stuff out. Not the food, it stays sealed, just the equipment.
I am not sure if you would need to be that pedantic, as well as the heat being that its rainforest here we have much higher spore loads of the more aggressive mold species, its often already on gear just from normal use, which is why we have to be overkill with inspections.
Interestingly I had been rotating my white rice out every two years, as per the packet life(and my understanding of when rice goes 'rancid' ) but had not been tasting it. A friend of mine produced a stockpile of white rice he had stored in the intense heat here in well sealed boxes for 9 years and it was still edible! So no more throwing rice out for me . I'll taste a packet and if its good the rest can stay