Can you wear suede shoes in the rain? Yes. Namor treated his suede loafers with Red Wing’s silicone spray, and shows us how waterproof they are now. I personally use Allen Edmonds’ Spray Waterproofer, but the effect is the same. Note that Allen Edmonds’ isn’t silicone based. There’s some controversy over whether silicone products can damage your leathers, but I’m not sure there’s any conclusive evidence either way.
Addendum: I don’t recommend using these waterproofers on any smooth calf, but I’ve done it to all my suede shoes without any harm.