Portland Head Light, seen from South Portland's Willard Beach, shines through swirling sea smoke just after sunrise on Saturday. The "smoke" is water vapor forming when cold air moves over relatively warm water. Credit: Troy R. Bennett / BDN

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A front-page story in the Feb. 4-5 edition of the BDN, “An Arctic blast” (from The Star-Herald in Presque Isle), purported to report that Aroostook County and other regions were “expected to see their lowest temperatures in recent memory.” The piece then goes on to discuss this only in terms of splashy and sensational “wind chill” temperatures. It never mentions actual air temperatures.

As a 2014 Scientific American article explains, “Your skin temperature cannot drop below the actual air temperature … Wind chill is a mathematically derived number that approximates how cold your skin feels — not how cold your skin actually is.” This is pretty dodgy science, but with winds topping 40 mph this past weekend, the wind chill numbers are far more spectacular than actual air temperatures. Up until a few decades ago, neither “wind chill” nor its warm-weather analog “heat index” were ever uttered.

So, is the truly significant number wind chill, derived from some fuzzy algorithm, or actual air temperature? As the Scientific American article says, wind chill only “approximates how cold your skin feels — not how cold your skin actually is.” That’s a pretty subjective “measurement.”

This distinction is important and deserves clarification in any serious reporting of temperature records.

Rick Lindquist