The nocturnal valley atmosphere is characterized by a strong and 900m deep stably stratified boundary layer. During the day, no pronounced well-mixed layer with a capping inversion develops in the valley. Above a super-adiabatic surface layer of about 150m depth, a stably stratified layer prevails throughout the day. However, heating can be observed within a layer above the surface 800m deep. Heat and moisture budget estimations show that sensible heat flux convergence exceeds cold air advection in the morning, while both processes compensate each other around noon, such that the temperature evolution stagnates. In the afternoon, cold air advection predominates and leads to net cooling of the boundary layer. Furthermore, the advection of moist air results in the accumulation of moisture during the noon and afternoon period, while latent heat flux convergence is of minor relevance to the moisture budget of the boundary layer.