So I have lived in the Bay Area my entire life (over 40 years now) and I can tell you to use SF and definitely NOT Stockton.
Oakland, especially the stadium is only just on the other side of the bay from SF

. using this great site (
Gmaps Pedometer) I determined the two stadiums are just over 10 miles apart.

We live in Brentwood, a suburb roughly 40 miles east of SF, with Stockton another 20 miles east of us. However there are 2 mountain ridges between us and the city and it makes a HUGE weather difference. Between SF & Oakland is just the bay.
I will give you an example from last week. Last Saturday I was watching the giants on TV and in SF at gametime it was 70*. At our house.just 40 miiles away it was 105*!!!! Stockton is typically another 1-2 hotter than we are.
So, short story long (I think I just needed to vent about how damn hot it has been) You should feel very compfrtable using SF as Oaklands weather data - they are virtually identical.