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John Wheeler, WDAY, Published December 19 2012

Weather Talk: Reality of wind chill index not as precise as equation

The formula for the wind chill index is as follows: WCI = 35.74 + 0.6215T - 35.75V (**0.16) + 0.4275TV(**0.16) where T is the air temperature in degrees Fahrenheit, and V is the wind velocity in miles per hour, and ** stands for “to the power of” because the way this is traditionally written in mathematics does not correspond well to typed newspaper copy.

But the reality of wind chill is not nearly as precise as this equation looks. The fact is that people respond differently to similar weather conditions. Further, sunshine is left out of the equation and so is the fact that wind is officially measured at 33 feet above the ground, which is not where most of us encounter the wind. Wind does not actually make the air colder, it merely causes things to cool down to the air temperature more quickly.

The system is far from perfect, but it does at least offer a numerical guide for people to easily quantify the combined cooling effect of wind and cold.

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or write to WDAY Stormtracker, WDAY-TV, Box 2466, Fargo, ND 58108

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