The horizontal distribution of evaporation over a small lake surrounded by heterogeneous terrain is quite complex. It is therefore usually not possible to provide accurate evaporation estimates for the whole lake based upon a single observational site, even if this site is located offshore. In the present study, a numerical two‐dimensional terrain‐following mesometeorological model is applied to Lake Kinneret (area of 170 km2, located in northern Israel) to obtain appropriate spatial and temporal resolution of the climatic parameters needed to estimate evaporation. The model is verified by comparing its calculated evaporation rates with those measured at an offshore site by the eddy correlation system and by its ability to reproduce well‐established characteristics of the microclimate over the lake. Results indicate that, for the typical meteorological conditions characterizing the experimental period, a concave horizontal distribution of evaporation rate is predicted across the lake. Consequently, the assumption of a uniform evaporation rate over the whole lake equal to that at the measuring site could lead to a misestimation of the amount of water lost through the evaporative process.