Hi, I suppose it depends on the leather, but I put Aussie Leather Conditioner on my leather boots. Snow just falls off and no rain seems to get in, either.
This Aussie stuff is great, really. I stripped an old gun stock with Nitromors, rinsed it, and applied a few coats of the conditioner, applying gentle heat from a hairdryer between coats.
Looks like a perfect oil finish!