It would seem many drivers in California still don't know since summer 2005, one must have headlights turned on when windshield wipers are in use due to rain, snow or fog. On my 15-minute drive to the gym today, I must have seen at least 7 cars without their headlights turned on.
These are probably the same drivers that talk incessantly on their cell phones and hold up traffic because they are engrossed more on their conversation than they are on driving.
Please turn on your headlights. This is to make yourself visible to other cars, pedestrians and cyclists. And while you're at it, hang up, shut up and drive. It can wait until you've reached your destination.