The heat absorbed by the air during the diurnal temperature rise is computed for Oklahoma City. Insolation measurements are recorded for each day, and the energy that is not used in raising the temperature is assumed to represent an empirical integration of the other terms of the local energy balance. With this empirical value taken to be the sum of energy losses, computations are made to show the ratio of the energy loss to the total insolation. These ratios of energy loss are correlated to the observed states of the ground. The computations are made for 141 days taken at random during one year. Eight ground states are used in the analysis and significance tests. The results show that the state of the ground affects the energy balance to such an extent that errors of 4° F. or more in maximum temperature forecasts may be due entirely to the effect of the state of the ground.