Measurements have been made of the absorption of sound in air at13‐octave frequency intervals from 2000 to 12 500 Hz, as a function of humidity, at six temperatures in the range from −0.5° to 25.1°C at normal atmospheric pressure. The results of the new study are presented and compared with those of past investigations. Then a “best fit” is obtained to existing data. The resulting information is presented in both tabular and graphical form, useful for the solutions to problems of the calculation of attenuation of sound propagated in the atmosphere and the computation of the effects of air absorption in problems of room acoustics. These results have been extrapolated downward in frequency to 125 Hz and extrapolated to cover the temperature range from −10° to 30°C at normal atmospheric pressure.