It is fine to wear the shearling coat in mild rain or snow. You just have to shake off the water or ice when you reach home and let it dry in an open and airy space. Then, brush off the stains. It will make your coat or jacket look as before. But you should not wear it in the pouring rain as it will ruin the fabric. Keep in mind that with proper care, you can keep your jacket last for years and even generations.