What is a typical dress code for campus interviews on west coast state schools?
I'm honestly just guessing here, but I'd think something along the lines of Business Casual or Smart Casual. Both of those are ambiguous, of course, but I think you'd stand out in a suit. 

Of course San Francisco is more formal than LA or Berkeley, but academics in most fields are pretty laid back. If the interview will be long and includes evening events, you might want to have a suit available.