few things to remember in socal rain:

1. It rarely rains, so all the oil and grease comes up on the first rain. Makes for slippery corners. Avoid turning on the white painted road markings.
2. It rarely rains, so many people have dryrotted wiper blades. They can't see anything and they are not looking for cyclists on a clear day....
3. Rain won't make you sick, but that cold will. If you get a rain jacket, you can layer up to kill the chill.
4. Your brakes won't work until the water squeegees off the rim- so when you want to stop, grab the brakes gently a few times to do that.
5. You get a lot of junk in the drivetrain and it's best to clean everything so you don't get rust and corrosion. If you have a steel frame, spray the inside with some wd40