Yes, it can get hot Timothy. I keep mine in a spare room, with the curtains closed to keep out the sun. Super8 is stored in a cupboard in the dark in the same room. I was sorry to see all these rusty cans. The material was probably quite rare, and left for much longer the cans could be beyond saving. Don't know what the condition of the films inside would be.
I was told by someone that had been to Pinedene Films, that the owner doesn't know what he has, and the films are all in piles in a shed, and the one you want might be at the bottom of a 16mm pile. It's risky, as you don't know the condition of the films.