Yesterday, John McCain told supporters in Iowa that U.S. soldiers are "carrying 40 pounds of body armor in 130-degree temperatures." Run a quick Google News search, and you'll find numerous references to Iraq's sweltering "130-degree" weather. It's in the Philadelphia Daily News, the Providence Journal, the Tucson Citizen, Wired, and even on military blogs. But according to this government Web site, the highest temperature ever recorded in Asia is 124 degrees—in Dhahran, Saudi Arabia. So, how hot does it really get in Iraq?
The temperature never breaks 130 degrees, according to official climate records. A 2007 Air Force Weather Agency report on Iraq's summer weather also marks the record at 124 degrees, with mean highs for July and August at 110 degrees. And Iraq is always dry, so the heat index won't be much higher than the actual temperature.
Then why do so many people talk like 130-degree temperatures are a daily occurrence in Iraq? Bad equipment, for one thing. Soldiers and travelers often measure the temperature with personal thermometers, which tend to give inaccurate readings. Command posts sometimes place thermometers on their outside walls or other locations within their encampments, but these thermometers are also cheap and unscientific; one solider described them as the kind of thing you'd pick up from Wal-Mart or see in someone's garden.
But even a perfectly functioning thermometer, if placed on a solid surface, is likely to deliver higher readings than one set up in an open, breezy area. In general, a solid object absorbs more heat than an equivalent volume of air and can rise to a higher temperature given the same amount of sunlight. An instrument placed on sand or concrete will absorb heat from that surface—obscuring (and inflating) the actual air temperature. So, depending on where it's sitting, a surface thermometer can be off by more than 10 degrees. That's why professional meteorologists prefer to measure the temperature in a ventilated location, and never set up their instruments on heat-conducting surfaces like sand, concrete, or asphalt.
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Explainer thanks Bret Hayworth of the Sioux City Journal, Paul Rieckhoff of Iraq and Afghanistan Veterans of America, and Scott Stephens of the National Climatic Data Center. Thanks also to reader Dave Anderson for asking the question.