Can it truly make a person susceptible to a cold/flu by walking in the rain?

Maybe: If the body is significantly taxed it can lower immunologic resistance/ reserves with which we fend off viral infections. A virus is required to catch a cold. Cold, dry air ^’s nasal mucus production & viscosity. Mucus is part of our body’s defense mechanism. It traps viruses & other particles. When the mucus is thick (sluggish) it makes removing viruses more difficult. Another function of the >.