The use of the geostationary meteorological satellite Meteosat for the estimation of rain is well known. We have used the two thermal infrared channels of the polar orbiting satellite NOAA-9/AVHR.R to obtain relations between surface temperatures measured by the satellite and rainfall measured on the ground in Senegal for the rainfall season 1987. The two channels were combined using the split window technique with the coefficients of Lagouarde. The results give high linear correlation coefficients and show that the average surface temperatures could be used as good indicators of rainfall for the same period.