i (rightly or wrongly) store paint in pots between uses, however, i dont fully fill them, and i do try to rotate them regulaly to stop them from getting flat spots
i dont really know mate, its more to do with humidity i think, look on the side of a box of paintballs and it tells you what is the ideal storage conditions, i have a flametech heated bag, so temperature doesnt really affect me
humidity ie water vapour in the air comes into contact with the paintball. the paintball absorbs the water causing them to swell up and increase in size+go all squiggy.
i think(not 100%sure) the cold weather causes the shells to become more fragile and can someone cause cracks in the shells.
heat or directly sunlight causes them to expand like all things.
id be more worried about humidity to be honest.
just keep them at about just cooler than room temp and ull be fine.
Once upon a time someone told me that long term paint storage should be at T-Shirt temperature - whether that's Northern T Shirt Temperature or Southern T Shirt Temperature i'm not sure.
i always thought that hot weather would make the shell all soft and rubbery i.e go very soft as the shell is hot and goes all squiggy, and wouldnt the cold weather make them go hard and make the balls shell alot harder thats why winter balls have a thinner shell so they break on impact and dont go through your arm or leg like a bullet
i dont think either hot or cold are worse for your paint. I am having a nightmare with my paint being too brittle now its cold though. But if the paintballs swell from the heat they will chop in your barrel.