Frequency and consistency analysis permit a differentiation of channelling effects dependent on geostrophic and surface wind directions for the valley-like mountain basin Baar in southwest Germany. During the day, dynamically forced and thermally driven channelling effects are evident, whereas during the night, thermally driven and pressure-induced channelling effects predominate. As a result, quasi-periodic variations of surface wind directions occur daily. The greatest consistency of these wind directions appear during the daytime in connection with forced channelling effects and during the night as a result of thermally driven channelling.