I stayed at the LW resort about 7 years ago, it always seems quite a bit warmer in the summer than say standing at the 15/76 junction for what ever reason, but I will admit I have limited experience in that area other driving through and stopping a few times.
And yes SoCal has always been on a super growth path, there have been many times in the past that SoCal was declared dead but it always comes back. Asia is where I see the biggest influx of emigration these days (not Mexico).