Change to precipitation in a warming climate holds many implications for water management into the future, and an enhancement of a precipitation decrease or increase on or around mountains would have numerous impacts. Here we show that recent observed trends and two high-resolution model ensembles agree on an enhanced precipitation decrease over the Australian Alps compared to surrounding regions in winter and spring, consistent with theory and model studies of idealised mountain ranges. The ensembles disagree on an enhanced precipitation decrease in autumn. Intermediate resolution modelling suggests that this enhanced response is present over other mid-latitude mountain ranges in winter. The projected change in summer rainfall over mountains depends on processes such as convection that are parameterised even in current regional climate models. We find that parameterised rainfall drives an enhanced rainfall increase over the inland slopes of the Australian Alps compared to surrounding regions in summer, partly consistent with previous findings over the European Alps. We also find that an increase in parameterised rainfall determines the sign of total rainfall change in many regions in summer, only some of which are on or near mountains. The results represent regional-scale added value in the climate change signal of projections from high resolution models in cooler seasons, but suggest that the specific model components such as convection schemes strongly influence projections of summer rainfall change. Confidence in the simulation of change in convective rainfall, or convection-permitting modelling may be needed to raise confidence in summer rainfall projections over mountains.