Rain can damage leather if oils are not applied to the surface. Once leather dries after being wet, it can be ruined and impossible to repair.
After leather gets soaked in the rain, therapeutic oils should be added to the surface before it has a chance to dry out. The oils will help to condition the fibers located deep within the surface of the leather. Rain, or any type of water, will likely wash away any existing oils so they must be replaced to keep the leather in pristine condition.
This type of leather care is relevant for any leather product, whether it is a saddle, purse or shoes.