I was in Las Vegas on business in August and it was 114 on the Hoover Dam. The next day, we did a helicopter ride with lunch in the Grand Canyon and it had cooled to 112 degrees.
It may be dry but 114 is still 114. I lived in New England for a few years and even with humidity, it never felt like 114.
To compare, put your oven on 450, let it heat, stick your head in. That's what it's going to feel like in Las Vegas in August.