Glad to help,
At Big Caliente, the tempature depends on where the valve is set. There is a valve that controls the hot water in flow. So it just depends on where it was before you get there. If you hike past there about 100 yards there is another set of pools, recently built. They are called the anniversery pools. The h2o there comes down the hill directly to the pools, via a hose. So if the hose is going straight in it is very hot. As was the case upon my arrival, @ 120 degrees. So I removed the hose and returned about 4 hours later to find the place cool enough. But some one had trashed the place. Even the h2o was beer colored. Camping at the springs here is prohibited, but is allowed @ 200 yards going back toward town. Where there is a large Oak tree for shade and a picnic table also. Also There are other camp grounds past the rangers station that you go past @ 1 mile before the springs. There is an info kiosk that usually has a good map of the area here. If not just turn right as you get back to the main road and you will see at least three that I know of. This is also the direction to Little caliente. The camp grounds are free.
The temp at Little Caliente was 108 in the upper pool. 107 in the middle pool, and104 in the lowest pool.
Coming from Las Vegas the air temps were great, 85 tops and 70 at night. You probably want to bring some bug screen , as the nats seem to have fun just before sunset. I hope that helps.
HAPPY SOAKING :~)