Oh heck yeah. Right now there's probably no natural water between the border and Lake Morena. There's 20 miles right there.
There's probably no natural water again for another 17 miles, and I'm just assuming Long Canyon is still running.
I'll go ahead and call pipe springs natural, but from Lower Morris Meadow to Oasis Spring there's nothing natural flowing right now. That's only about 9 miles, but the next is a whopper.
I very seriously doubt there's any natural water from Oasis Spring until Barrel Spring. That's over 50 miles.
Fortunately we have some reliable piped water and a couple caches and water tanks. Those aren't natural though. If you insist on natural you better be an incredible hiker or wait until another time.
Next week I'll try to provide updates for everything from Devils Slide to Hwy 74. I was actually hoping to bump into some south bounders next week, but it looks like all of them have already finished.
It depends. Idyllwild has much warmer temperatures compared to the trail several thousand feet above it. Much less wind too. Warner Springs, Laguna and Lake Morena is exactly like the trail because the trail literally runs through it.
If you want warmer nights you can still have it, but you have to make it happen. Drop to lower elevations, being aware of air flow patterns, sleeping among trees and on thick forest duff will help you stay warmer. You don't always need all of that either. On October 22nd I slept near Fred Canyon on thick forest duff and under trees, which kept me so warm that I pushed my quilt down to my waist most of the night. A couple days later I wasn't as picky when I camped in the Lagunas and it was much less pleasant.
What you may want to do is try contacting some south bounders. They should be able to give you the best information on water in southern California.