code: def wind_chill(temp, wind):
      
      if temp is None or wind is None:
          return None
      wind_kph = wind * 3.6
      if wind_kph <= 4.8 or temp > 10.0:
          return temp
      return min(13.12 + (temp * 0.6215) +
                 (((0.3965 * temp) - 11.37) * (wind_kph ** 0.16)),
                 temp)
docs: Compute wind chill, using formula from
      http://en.wikipedia.org/wiki/wind_chill