This work combines two established models for precipitate growth in the bulk and at the grain boundary to investigate the growth of pure Si precipitates in the alloy AA6016 during slow cooling after hot rolling. Despite the simplicity of the approach, the predicted phase fractions and the predicted width of the precipitate-free zone are in agreement with the measured values. The model predictions suggest that ­raising the Si content and increasing the density of primary Fe-based particles reduces the fraction of grain boundary precipitates. The model correctly reproduces the technologically important effect of the cooling rate on intra- and intergranular growth. The model predictions can be used to optimize hot rolling schedules and the alloy design.