A new data reduction technique for measuring the convective heat transfer coefficient is reported. The technique is based on the evaluation of the Fourier transform of simultaneously measured freestream temperature and surface wall temperature or heating power. Any wave shape can be used to heat-up the stream or the wall and the method yields information redundancy on the local heat transfer coefficient. Effects of various uncertainties on the accuracy of the heat transfer coefficient evaluation are considered and quantitatively analysed. A numerical simulation of the effects of noise on the measured temperature signal is also reported and discussed. (C) 2003 Elsevier Ltd. All rights reserved.