Proposed evolutionary histories of solar luminosity, atmospheric carbon dioxide amounts, Earth rotation rate, and continent formation have been used to generate a time evolution of Earth's surface temperature. While speculative because of uncertainties in the input parameters, such a study does help to prioritize the areas of most concern to paleoclimatic research while illustrating the relationships and mutual dependencies. The mean temperature averages about 5 K higher than today over most of geologic time; the overall variation is less than 15 K. The evolution of Earth's rotation rate makes a significant contribution to the surface temperature distribution as late as 0.5 b.y. ago. While there is little change in equatorial temperatures, polar temperatures decrease, being some 15 K lower 3.5 b.y. ago than with present day rotation. The effect of continent growth on albedo is of secondary importance. ¿ American Geophysical Union 1989