I haven't seen the campus or ever been there - generally try to say away from NoCal.
The baseball program isn't great, but they play in a fairly good conference. At any rate, they said he would be starting & playing immediately. Maybe if the program isn't that good, he will stand out - kind of like the one-eyed man is king among the blind.
Yes, I believe it will be cooler there, but not as cold as SF, from what I can gather.
He doesn't know anybody there. I doubt if anybody from Santa Ana goes on to UC Davis. They are basically worlds apart, from what I would imagine.