Just make certian that the powders remain DRY. I have some metol left that I had bought in 1972! Still just as good.
Now, I use PET plastic bottles (of course, thoroughly washed and even more thoroughly DRIED) for all storage of powders. (I also store salt and food-stuffs in PET plastic bottles, but, if you do, make certain to label properly; I once had a guest who almost helped himself to some 'apple juice', which was really Dekol stock solution!)
Hot or cold will NOT affect powdered chemicals. I have had a darkroom since 1964. - David Lyga