Three-dimensional versus 1D temperature structure for stellar parameters T_eff=5773 K, log ɡ=4.7, and metallicity [M/H]=−4.0. The orange band outlines the 3D temperature distribution of the high-resolution model resampled to 70 × 70 × 160 grid points. The width of the temperature distribution encountered on surfaces of equal Rosse-land optical depth is indicated by the dashed blue lines enclosing 95.5% of the data points at each height. The solid black line shows the average temperature of the 3D model, the long-dashed black line represents the T(τ_Ross) relation predicted by a 1D model atmosphere with identical stellar parameters, treating convection by standard mixing-length theory, but otherwise using the same input physics as the 3D hydrodynamical model.