The magnitudes of water surface temperature fluctuations induced by surface waves of known dynamic characteristics were measured. An infrared radiometer, capable of detecting temperature changes less than 10-4¿C with response only in the 8- to 13-μm spectral region, was the prime diagnostic tool. The major experimental task was to discriminate between the thermal and reflectance contributions to the wave-induced total radiometric signal. A technique which measures the upper bound of the reflectance contribution was developed, validated, and implemented. The magnitude of the measured temperature fluctuations induced by small amplitude monochromatic surface waves of near-ideal characteristics agreed well with predictions from linear theories. In the linear wave dynamic regime the amplitude of the wave-induced temperature fluctuation is dependent upon the near-surface heat transfer. This dependence was found to be linear by systematically increasing the surface heat transfer by means of an increase in wind velocity.