We rode through TX, NM, and AZ last August
. I wore the ADV jacket (and pants) sans collar the whole way. It wasn't pleasant, but we only had to stop for gas and refilling of the 3l bladder. Temps topped 115F through Phoenix and the gear at that temp actually protects you from the heat as long as you stay moving and hydrated. At one point traffic slowed to stop-and-go in Phoenix and the bike was headed to overheating so we got off the highway and stopped for a while. Sitting in stop and go traffic on an overheating bike in full gear in 117F
is no one's definition of fun I don't care what you're wearing. I also wore the full gear in May in Moab
last year on the 530, but that was "only" 95-100F. The gear is hot, but it carries 3l of water, and as long as you fill it with ice and water, it will help cool for a few hours and hydrated a few more.
just another data point...