Rain is ok for the bike. You just will need a little more maintenance. Clean the bike with one or more brushes and a pail of warm soapy water. Then lightly spray it with the hose. This will help keep the road grit and grime off. Wipe the chain two or three times to just make sure its fairly clean and dry. In heavy rain, I'd usually use two plastic bags: one for my seat and one for my work clothes in the backpack. A rain jacket or shell can;t hurt, either. I don't bother with a hood for the rain jacket. But if yours has one, then by all means use it (if not too hot). You will also need to take apart, clean and lightly lube: stem & bar, cranks, BB, and seatpost more frequently. If not, then you *will* get creaky bike. Also plan on replacing your headset bearings every year. The bottom one was always the first to go since some muck kicking up from the front tire would get in there. Fenders would help with that besides keeping you a little drier.
Last edited by ptempel; 10-27-20 at 11:36 AM.