Wet-Bulb Temperature from Relative Humidity and Air Temperature

An equation is presented for wet-bulb temperature as a function of air temperature and relative humidity at standard sea level pressure. It was found as an empirical fit using gene-expression programming. This equation is valid for relative humidities between 5% and 99% and for air temperatures between -20 degrees and 50 degrees C, except for situations having both low humidity and cold temperature. Over the valid range, errors in wet-bulb temperature range from -1 degrees to +0.65 degrees C, with mean absolute error of less than 0.3 degrees C.