windchill.py

    def getWindchill(self):
        """
        Return wind chill in degrees Celsius
        """
        # http://en.wikipedia.org/wiki/Wind_chill - North American wind chill
        # index
        if self.w_chill is None:
            if (self.temp and self.temp <= 10 and
                self.windspeed and (self.windspeed*3.6) > 4.8):
                self.w_chill = (13.12 + 0.6215*self.temp -
                                11.37*(self.windspeed*3.6)**0.16 +
                                0.3965*self.temp*(self.windspeed*3.6)**0.16)
        return self.w_chill

    def getWindchillF(self):
        """
        Return wind chill in degrees Fahrenheit
        """
        # http://en.wikipedia.org/wiki/Wind_chill - North American wind chill
        # index
        if self.w_chillf is None:
            if (self.tempf and self.tempf <= 50 and
                self.windspeedmph and self.windspeedmph >= 3):
                self.w_chillf = (35.74 + 0.6215*self.tempf -
                                 35.75*self.windspeedmph**0.16 +
                                 0.4275*self.tempf*self.windspeedmph**0.16)
            else:
                self.w_chillf = self.tempf

        return self.w_chillf