In regional climate models, how to resolve lake surface temperature is crucial to understanding the hydroclimate in water-dominated regions, i.e. the Great Lakes basin. If no lake model is implemented in the lake grids, a “search” option will be employed to extrapolate lake surface temperature from the closest water point with valid data, e.g. Hudson Bay and the Atlantic Ocean, which can cause obvious biases and even adverse effects. In this study, a one-dimensional thermal diffusion lake model within the Weather Research and Forecasting model is updated with a specific treatment of lake surface albedo for the Laurentian Great Lakes to improve the coupled air-lake model’s performance in the simulation of lake temperature and lake ice.