I doubt the temp will be that high...I live about 15 minutes away and the wind has been blowing for 2 months. Local highs actually feel much cooler. I know that it has been said already, but I must reiterate that the wind coming off SF Bay is not cold, it is bone chilling and will send you running for your car once the sun goes down. We have had family from St Louis tell us that they have never been so cold as their summer in San Francisco.
I love the track, yes traffic can be a problem, lots of walking, but the location is breathtaking. Even the wineries just to the North are fabulous. One lament, the viewing area mentioned earlier that is now an additional fee, is right before the scoreboards at 1320ft. Used to be the best spot in the house on Friday night....sadly now the finish line is way up track and thus not a very good viewing spot anymore. The main grandstand is a bit far away, but it's not THAT far. The overall experience is much better than the wooden bleachers on the spectator side.....plus something no one has mentioned....when you sit there, there is an annoying chain link fence that you look through to see the racing. It is really off-putting for me. Plus the main stand has easy access, lots of food options, permanent bathrooms, shade during the hot afternoon (if no wind that is).
Enjoy your trip and try to take in some of the local sites....it's a great area! Post your experience for us to read.
ted