I ride at the same area that you are in Southern California. I hate these jerseys. I feel like being in a condom. If you are not a hardcore rider, just put a big t-shirt on and go for a ride. Try to go to westlake village, its a bit cooler their and the late afternoon.
Last week we had over 100, and was brutal to ride. DOn't worry how you look be comfi and keep riding.