Shipping containers are the perfect way to protect your items from the elements. The raised marine ply floor of shipping containers mean that they will not absorb water from the ground. The all steel construction of a shipping container makes them wholly weather proof, even the vents are designed to ensure that water cannot ingress. Shipping container doors are also surrounded by weather proof seals.
It is important to remember that shipping containers are designed to travel the seas in detrimental weather conditions and withstand high saline environments. Stacked containers on a shipping container vessel or in a container yard are not protected from the elements, anywhere in the world, yet the thousands of goods that they carry around the world arrive with us, undamaged by the weather!
So, how weather proof are shipping containers? VERY!