If they are in a pot, above ground, they likely won't survive the winter. In nature, when a tree is growing in the ground, the roots are insulated by the sheer volume of the soil around them as well as snowcover on top of the ground.

So, either plant them now, if you know their permanent spot. Or, else you can dig a hole and sink the pot up to their rims for winter. Fill in around the sides of the pot with loose soil. This in effect will insulate the roots just as if the tree were planted in the ground.

Either way, when winter comes, it might not hurt to mound fresh fluffy snow around them to help protect them from the cold. Use fluffy snow, however, and gently place around the trees.

Glen