A method for estimating sea surface temperature (SST) from a single infrared (I R) channel together with an atmospheric model is investigated. Based on a simulated atmospheric height profile, the precipitable water and transmittance can be calculated as a function of height from the known atmospheric pressure, temperature and relative humidity on the ground. An effective transmittance (which is the ratio of the radiance at the satellite to that on the surface) is used to correct the effect of off-nadir scanner angle. Various data from the Heat Capacity Mapping Mission (HCMM), the Advanced Very High Resolution Radiometer (AVHRR) and other sources are used to evaluate the accuracy of the method. The SST derived agrees with available ground truth with a root mean square (r.m.s.) error of about 1 deg K. The apparent surface temperature varies with the scanner angle to produce differences as large as 8degK at 10·5–12·5μm in a moist summer climate at an off-nadir angle of 60°.