I like this quote, and used to keep a copy of it in my day planner. Today the day planner is on the phone
"Life is not about waiting for the storm to pass... It's about learning to dance in the rain." unknown
(DBrown, this might be in your neck of the woods, Lewiston, MI)
IMO you can ride one day of rain in just about anything, but without a way to dry your clothes every day a good set of rain gear is essential. For riding day after day in wet weather I find a good set of breathable gear with good synthetic base layers works well. Unless it is cold, I don't worry about my feet. If it is really warm, I don't worry about wearing rain clothes, except maybe the unzipped jacket. It keeps the things in my jersey pocket dry.
This was 50F, which appropriate gear makes riding in the rain relatively comfortable, even for several days in a row.