Rain dilutes the virus and can also physically wash it off a surface just like “dirt can wash away,” says Jared Baeten, professor of global health, medicine and epidemiology at the University of Washington. However, experts don’t believe rain deactivates the virus or disinfects surfaces the way soap and water does.
Scientists don’t yet know how much of the virus you have to be exposed to in order to be infected, says Jared Evans, a senior scientist at Johns Hopkins University Applied Physics Laboratory. So it’s unclear whether the already limited impact rain would have on viruses living on the surface of, say, the bannister of your front steps, would make a difference in whether or not the bannister is safe to touch.