Indeed. I've posted numerous times about our major temp differences in the Bay Area for a given hot summer day.
Examples at viewtopic.php?p=606051&hilit=walnut+creek#p606051
It's much cooler in places like near or next to the water like Pacifica, Half Moon Bay, city of SF or Santa Cruz. It's much hotter inland in places like Walnut Creek, Concord, Antioch, Livermore and Dublin. San Jose can get pretty hot and Gilroy tends to be hotter.
It can be pretty hot if you start from San Jose but if you go north, by the time you get to Daly City, it may have dropped 20+ degrees.