An analysis performed to determine the effect dust particles suspended in Mars' atmosphere have on the radiation the surface both directly and scattered by the dust is described. Additionally, the fraction of incident sunlight directly absorbed by the atmospheric dust is computed. These calculations are done for ranges of dust opacity &tgr;, incidence angle i, surface albedo as, and dust albedo ad, representative of the conditions on Mars. The effect of atmospheric dust on the Bond albedo is discussed. It is shown that direct heating of the atmosphere by dust absorption of solar radiation is adequate to explain Mars' south polar spring temperature inversion. Under the most circumstances the presence of dust in Mars' atmosphere produces a lowering of the average surface temperature; this is probably the cause of the anomalously slow south polar cap retreat of 1977. Explicit forms for both the surface heating and the atmospheric heating as a function (&tgr;, i, as, ad) are given.