A simple one-dimensional heat transfer model has been applied to estimating the surface temperature of concrete pavements and bridge decks. Using representative weather data from the NREL, the results indicate considerable geographical variability not only in the concrete surface temperatures, but also in the time-of-wetness and number of freeze-thaw cycles. This indicates that realistic estimates of service life can only be made when detailed consideration is given to the environment specific to the field concrete in question. The results of this model will be utilized as input to a Windows-based computer program for sorptivity-based service life predictions for the cases of sulfate attack and freeze-thaw deterioration, currently under development at NIST.