As part of my duties during my last tour near Baghdad, I ran a small professional meteorological station that logged temps (among many other readings) every fifteen minutes. Typically in July and August the high got to about 122 F, with the low aournd 4 AM about 93 F. And yes, it was over sand, because there's nothing else in Iraq. As others have pointed out, people don't hover in the shaded cool air. They're on sand and concrete because 99.96% of Iraq is covered in such. That's the killer: getting hit with not the ambient temperature, but standing in the sun on baking concrete, asphalt, or earth while kitted up in body armor, etc. I won't even mention using a portapotty during the afternoon. The only vegetation on my entire base was two palm trees (until a rocket burned on down).

It's ironic that one of the links at the bottom referred to a story on all the deaths in the US during heat waves of much lower temperatures. The heat in Iraq is much deadlier than a Chicago apartment during a 100 degree day.