Those domes are charcoal kilns. And they make very good igloos when you show up and it's 2 degrees and snowing. :)
Temps at ~sea level were in the 60s, maybe even 70s, during the day. At higher elevations (by the charcoal kilns) it was probably in the 50s give or take 5 degrees (ok, take). Every 1000 feet you lose a significant amount of heat and the kilns were at 6800 feet.
During the night it's probably 40-50 on the floor.