Being from the East Coast originally, we've always felt that Californians were lousy at driving in the rain mainly because everyone treats it like it's no big deal and drives the way they normally would. Meaning just as fast and with just as much tail gaiting. Thus accidents and scary moments on the roads. We have heard, however, from other people who say the opposite, that people in California are great drivers in the rain precisely because they treat it like it's no big deal.
So maybe we don't know what we're talking about. Or maybe we do.