Storing car in shipping container

I know they will accumulate moisture,dehumidifiers work in temps down to 60 degrees f, not the 40 as mentioned above.
There are units with heaters to prevent icing, but not feasable with an un insulated sea can. The big thing is air flow,none when humidity is high, lots when its low.
My 40x80 quonset has nil for moisture, one 2x2 vent on either end that are pretty much closed year round. Its on a cement floor too. Have not looked in my small canvas shelter lately, but i bet its damp. Its getting relocated in summer. Preferably onto a wood floor.