More advice from ChipSeal
Home after the commute in the rain, should the bicycle be put away wet? Yes and no.
Steve noticed grit everywhere when he was done acting like a six year old, (Fifteenth comment.) and you will have a grit problem whenever you ride in the rain or at a beach.
Road or beach sand acts as an abrasive on your chain, gears, brake pads and rims. This is the stuff we want to remove after a ride in the rain. Then we want to re-lubricate the chain.
First thing when you get home, before you dry off, grab a rag and a hose and spray down your bike. I recommend doing this on the front lawn. If it is still raining, and your neighbors notice you, it will confirm their suspicions as to your mental state! If they ask you about it just say; "Don't worry, the bicycle likes it!"
Your first target should be the undersides of your fenders with the bike on its side. This will stop all that crud stuck under there from falling down on the newly cleaned parts or messing with your parking space. (For ChipSeal, that would be his bedroom.)
Then stand the bike up and spray downward over the entire bicycle. A hard spray can force water into the frame cavity through cable guides, water bottle screws and other tiny holes. It won't hurt most bottom brackets, but it can be hard on any part that has iron in it. (If it is "real", if you know what I mean!)
After a quick rinse, open your brakes and and give the face of the pads a good hard spray. Run your fingertips along the face and dislodge any grains of sand lodged there. This will keep the pads performance top notch and prevent deep scoring of the rim, extending it's useful life.
Many brake pads seem to melt in the rain. You may find your rims smeared with black residue and streaks down your fork and seat stays. Now is the easiest time to remove it while it is still wet, and why you brought a rag. In my case, my reflective tape's performance will have been compromised by this phenomena.
After a final rinse of your rims and brakes, close your brakes to avoid a surprise and spray down all of your chain and gears. Hard spray is fine. Don't be afraid to overdo it. Then park the bike where it can drip dry and get out of your wet clothes.
Later, lube your chain. I use a two step spray and wax lube method. Sheldon Brown didn't, but said there were many legitimate camps. So I will describe what I do, and hope not to start any fights.
I use White Lightning Clean Streak degreaser. This will remove all the lube and dirt left on your chain, and displace all that water as well.
I use cardboard to protect my rims from over-spray and later, over-drip. Spray the Clean Sweep generously on the chain while rotating it back wards in your favorite chain ring. The wipe with rags for about five chain rotations. If it is still picking up black, repeat the process. Then let it air for about ten minutes.
I use Rock and Roll lubrication "Red", or as I learned from their product site, "Extreme". I follow their directions, and I use it generously. This is a wax based lubrication, and it suits my cycling because it resists collecting dust. I a ride a bit on dirt roads.
These extra steps will diminish the extra wear your bicycle receives by riding in the rain. I will not take them if there is little evidence of grit on the bike. Once you see a gritty bike, you will see it is not hard to see.
If you anticipate a long ride or commute in the rain, you may want to consider taking along some chain lube to apply.
I have found a few parts on my single-speed to have an inclination to rust. The bolts on my stem and water bottle cages. You may wish to give them a shot of Pledge Protection Plus.
My wet cycling shoes get stuffed with newspaper for about ten minutes, and then I take it out and replace it with more dry newspaper.
And now it is your turn. What do you do when you come home wet?