I don't live in Santa Monica, but both parks and sponsored gyms get EX raids. This article on this site: https://pokemongo.gamepress.gg/s2-cells-foundation-pokemon-go-design talks about S2 cells and how they're used to determine which gyms are eligible. I believe that for the last set of raids (and hypothetically going forward) they used level 13 as opposed to level 12 cells, but the methodology for determining eligibility is otherwise the same. That said:
1) Santa Monica is a hot spot for Pokemon Go with (I imagine) tons of spoofers and your chances to get a pass there are probably not that high relative to other less-trafficked areas.
2) If you're not going to be living there, getting an invite for an EX raid taking place 1-2 weeks later, after you leave, would be awful.
I would advise NOT raiding at eligible locations while you're there, unless you have a friend who can do the EX raid for you if you happen to leave before it's scheduled. I imagine you're better off finding out where the eligible gyms in your area are and raiding hard at those, especially since Niantic seems to be continuing to expand its invite system.
