Out of necessity, I went this past Wednesday. The temperature in Southern middle TN was 98 degrees with a heat index of 107. I have a scope that needed to be checked for tracking and had to "shoot the box" before the next high power match.
The shooting positions are covered by an eight foot metal roof and the roof is shaded by large, old age, oak trees. A slight breeze and several bottles of water helped me and my shooting partner, who needed to confirm zero with a different load, get through the afternoon.
The hottest match that I can remember shooting in was at Ft. Campbell with a high temperature of 104. That was some 40 years ago and I became a little smarter after that event. The coldest match was at the AEDC range in Tullahoma, TN with an air temperature of 38 but, a crystal clear day and bright sun made it feel like 42.
I may not be smart but, I am trainable, according to my wife.