Paired, simultaneous, AN/GMD-1 radiosonde flights released 10 to 12 miles apart show smaller differences in heights of pressure surfaces than would occur if previous estimates of radiosonde error are accepted. The radiosonde system apparently delivers temperature information accurate to 0.3C (RMS error), exclusive of the solar radiation and response time errors of the thermistor. A table of errors for computed values of height and density at specified pressure, and of pressure at specified height is presented, based on this temperature accuracy.