i spent about half of an august in the davis mtns & big bend area, 1992 iirc.
really spectacular, but the august week i spent in organ pipe national whatever was warmer & drier.
both are great places to go.
this august i will be in E. WA...the difference between the eastern WA desert & the SW is that in WA the sun is up like 17 hours a day in summer.
last summer i was in E. OR, the sum goes down at 9 & the nighthawks come out in droves & they make this annoying buzzing noise that keep you up, then at around 4am the robins start singing, so you really do have to get drunk & take a nap in the afternoon...