I just wanted to confirm what I think I'm seeing. Starting Wed. morning, we will be driving up the coast form LAX to SF and to Napa. It sounds like the weather will be cool, as in the upper 60's along the coast, but warmer in Napa? Is this correct? I want to wear shorts, but now I don't know.. How cool will it be in SF? We'll be taking a Gray line tour of the city and going to Alkatraz on Sat.