Watching the Australian Open and they use a heat stress rating to protect the players. I've searched for the details of how it is calculated without success. Anyone know the formula that they use? Just curious.
where T is temperature in degrees F and RH is relative humidity in percent. HI is the heat index expressed as an apparent temperature in degrees F.HI = -42.379 + 2.04901523*T + 10.14333127*RH - .22475541*T*RH - .00683783*T*T - .05481717*RH*RH + .00122874*T*T*RH + .00085282*T*RH*RH - .00000199*T*T*RH*RH