Well LOL - I had to get a California driving licence... er, I mean driver's license - quite some years ago now. I got all the info from the local DMV office. I was transferring from IL though, and only had to do the written, not the road test, but all the info was in the handbook they gave me.
Pei! LOL - the Californian drivers I knew were terrified of rain. In fairness, I should say not without reason. It practically never rains at all from May to Sept., and doesn't rain much in the other months, except Feb/March when it can piss down, so they're not used to it. After so long without rain, there will be an oil build up on the road surfaces which is hazardous when wet. It takes a while for the rain to wash it away. The other problem is that many of their freeways are constructed from that concrete stuff, not tarmacadam. Stopping distances are a lot longer on concrete - especially when wet - and there's a lot more tyre noise. So I can see why they don't like driving in rain.