they changed the wind chill formula in november 2001.
they changed the wind chill formula in november 2001.
when did they change the wind chill formula?
november 2001
in november 2001, canada, the united states, and the united kingdom implemented a new wind chill index developed by scientists and medical experts on the joint action group for temperature indices (jag/ti). it is determined by iterating a model of skin temperature under various wind speeds and temperatures using standard engineering correlations of wind speed and heat transfer rate. heat transfer was calculated for a bare face in wind, facing the wind, while walking into it at . the model corrects the officially measured wind speed to the wind speed at face height, assuming the person is in an open field. the results of this model may be approximated, to within one degree, from the following formula:
wind chill
the standard wind chill formula for environment canada is:









































when the temperature is and the wind speed is , the wind chill index is −24. if the temperature remains at −20 °c and the wind speed increases to , the wind chill index falls to −33.









































the equivalent formula in us customary units is:









































windchill temperature is defined only for temperatures at or below and wind speeds above .
wind chill