The effects of sound speed fluctuations on various measurements made with sonic anemometers are derived. Corrections due to temperature-generated sound speed fluctuations on measured statistics are estimated from the 1968 AFCRL Kansas data for different stability conditions. For most statistics, the corrections were not large: the maxima were −3.5% to the measured horizontal velocity, vertical velocity covariance ( , proportional to the Reynolds stress) and −8.2% to the measured horizontal velocity, temperature covariance ( , proportional to the horizontal heat flux) for unstable conditions. It is also shown that the measured cospectrum of uw is contaminated by the cospectrum of uθ; in the inertial subrange of frequencies, the measured uw cospectra for the AFCRL data for unstable conditions were calculated to be high by 5–11%.