In order for wind chill to be calculated, the air temperature must be at or below 40 degrees Fahrenheit, the NWS said. Finally, the formula assumes that measurements are taken at night ...
For the Fahrenheit-faithful ... you're likely to use the following formula: (Temperature in C elsius * 1.8) + 32 to get the temperature you're more used to. B ut why is minus 40 still minus ...