Clumping seasoning

Does anyone have any tricks for keeping seasonings from clumping ove time when they sit? At home I have zero problems, I’m guessing because we have central air. The stuff I have at the cabin clumps up within a few weeks it seems like, I’m guessing because we don’t have air conditioning there. Would a person be better off putting the stuff in the fridge maybe or is that an even more humid environment?

Vacuum seal anything that has been opened.

That never even crossed my mind. That would solve all the problems. Thanks!