Previous work by K. A. Tryka et al. ( Science 261, 751-754, 1993) has shown that the profile of the 2.148-μm band of solid nitrogen can be used as a "thermometer" and determined the temperature of nitrogen ice on Triton to be 38 +2 -1. Here we reevaluate that data and refine the temperature value to 38 ± 1 K. Applying the same technique to Plato we determine that the temperature of the N 2 ice on that body is 40 ± 2 K. Using this result we have created a nonisothermal flux model of the Pluto-Charon system. The model treats Pluto as a body with symmetric N 2 polar caps and an equatorial region devoid of N 2. Comparison with the infrared and millimeter flux measurements shows that the published fluxes are consistent with models incorporating extensive N 2 polar caps (down to ±15° or ±20° latitude) and an equatorial region with a bolometric albedo ≤0.2.