Let me share a little observation of mine with you:
California's weather does not follow logic, common sense, or any of the laws of universe for that matter!
Consequently, the "weather forecast" is a silly concept used to make outsiders believe that we are high tech and weather-civilized!
Basically, whatever the forecast tells you its gonna be like the next day, does not mean SHIT about how it is actually going to be like the next day :)
So those of you who are traveling to Cali and are trying to figure out what to pack, I've got two word for you:
GOOD LUCK!
and for myself, living here for 8 years and still nagging about it over here, I've got three:
GET OVER IT!