Seasonal differences in the model sensitivity are found and are most evident during daytime. The largest differences in the seasonal sensitivities are associated with parameters used to calculate the length scale in the MYNN scheme and to some extent the value of the Prandlt Number (Pr). These differences are more apparent at the Vansycle Ridge and Hanford locations than at two wind farms located within the domain. The differences in the sensitivity can largely be explained by seasonal changes in the static stability over the region. An increased frequency of stable conditions during daytime would be expected in the winter compared to spring or summer. As the most influential parameters are those applied in the calculation of the length scale during stable conditions, one would expect an increase in the daytime sensitivity with the increase in frequency of occurrence of stable conditions during the day. The increased sensitivity of the simulations to Pr seen during over the basin in February is surprising. In the formulation of the MYNN parameterization, the value of Pr impacts the simulated sensible heat flux regardless of the stability. The sensitivity to this parameter, however, could be related to the differences in temperature gradients seen in stable verses unstable conditions. It is also interesting to note that the sensitivity to Pr is relatively large in areas where the sensitivity to turbulence dissipation rate is relatively small.