This study compares several methods of computing daily mean values of dry bulb temperature, dew point, and relative humidity. Data are daily observations at nine selected points in the contiguous United States for 5 years of record during the mid-season mouths of January, April, July, and October. Daily mean values of the three elements were computed from the four synoptic observations (sum ÷ 4) and from the 24 hourly observations (sum ÷ 24). Also, for dry bulb temperature and dew point, they were computed from the daily highest and lowest hourly value (sum ÷ 2). With the mean of the 24 hourly values as the base, daily departures of the means computed by the other methods were determined. Averages and standard deviations of these daily departures were computed for each station-month for the 5-year period. These were mutually compared, with the conclusion that when the methods tested are applied to dew point and relative humidity, the departures from the 24-hour mean are generally no larger, and in many cases are smaller, than those obtained in computing daily mean dry bulb temperature by the same method.