On frigid winter mornings, when weather forecasters are trying to describe whether it’s a hat-scarf-gloves day or if just a warm coat will do, they will take the temperature (T) and wind speed (V) and plug the numbers into a handy equation: WCT = 35.74 + 0.6215T – 35.75V0.16 + 0.4275TV0.16.

The result is the wind chill index, a number that attempts to tell us how cold it might feel rather than simply how cold it is. It considers wind, in addition to temperature, to calculate the loss of heat from the body.

The National Weather Service had been calculating the wind chill since the 1970s, but not very accurately, until two scientists set out in 2001 to perfect the measure and make it more reliable. One of the two was Maurice Bluestein, who died at 76 on Aug. 28 in Pompano Beach, Fla., where he lived. His daughter Karen Bluestein said the cause was esophageal cancer.

Dr. Bluestein, who was trained as a mechanical engineer, had not given much thought to the science behind the weather until he was shoveling out his daughter’s car from under a snowdrift one evening in January 1994 in Indianapolis.