not a lot of places super close to LA that won't be super hot, unless you could head to elevation. If you are set on climbing, VD wall in the south area is pure shade in the morning. Get there early and do a half day before it turns into sun. Its also the wall that has the most moderates.
I climb there pretty regularly. I have only really done routes on the South side - when I climbed North side, rock quality was a pile of choss as I don't think it gets much traffic. I wouldn't go there now - way too hot (even in the shade).... but if you do go, I would get an early start and know which routes you want to do because it got pretty warm around 7 am last weekend.