Re: Reloading room temps'.
get yourself a refrigerator. They make the ideal storage cabinet for powders and you should be able to find a dead one somewhere for little or no cost, other than the time and energy to haul it away. Dosen't need to work, no need to plug it in. What you're after here is all that insulation; it'll keep the powder inside relatively cool and at a fairly stable temp.
Extreme cold is bad for powder. Extreme heat is far worse. The temperature swings between the two are a real problem and will hasten powder breakdown and deterioration. And old refrigerator or freezer chest will go a long ways towards resolving this for you.