An experiment was performed in order to investigate the effect of radiant heat on wet bulb temperature measurement. It was found that the radiant heat affect the natural wet bulb temperature and this effect becomes larger as the radiant heat level becomes higher and air velocity becomes lower. This radiant heat and air velocity effect on natural wet bulb temperature is quantified. Also, a set of relationship between unshielded and shielded natural wet bulb temperatures under various radiant heat and air velocity was found.
