I keep the third part of my backup on an External Hard Drive, a WD My Passport, which is kept in a Fireproof Box, with the rest of my household Documents, down the bottom of the garden in a shed. It is perfectly dry but, at this time of year, gets very cold.
My question: When I bring it in, each Sunday, to do the weekly incremental backup. Should I leave it an hour or so, to return to room temperature, or does it not really matter?
I don't know what is in your box but if I lived in a flat and the floors collapsed in a fire I think it would be the least of my worries. Clearly the contents are important enough to you to consider these possibilities so why not have 2 copies. Hard drives are cheap enough and copies of important documents can assist if you need to obtain originals. I hope you do not have this misfortune anyway and I would also let it warm up first. I would also think that frequently changing the temperature of something as sensitive as a hard drive would not be good for its longevity.
The Fire Box is made of polystyrene filled with some form of powder.
The fire safe contains Insurance Policies and a record of the contents of the flat. The Hard Drive, my Accounts and Tax Papers and my derided Autobiography, as well as the usual family detritus. I also have a NAS Drive in the Flat which handles daily backups but that is, so they say, not safe from Ransom Ware
It may be silica gel powder which needs to be "cooked" occasionally to drive off any moisture it has abbsorbed.
Cold does not hurt disks. Moisture in the form of condensation will unless dried out before use.
This thread is now locked and can not be replied to.