Sime and Wolff discuss our local hypothesis for the orbital variability in Antarctic ice cores2 by analysing the stability of Antarctic accumulation as simulated by the HadAM3 atmosphere general circulation model (GCM). They propose that a shift of the accumulation maximum towards austral summer in colder climates could dominate the weighted insolation and therefore mask the relationship of the accumulation-weighted signal and Northern Hemisphere summer insolation. We show that the applied model approach is inappropriate to evaluate the accumulation seasonality as current global GCMs are not skilful at modelling present and past accumulation seasonality at the core sites. Furthermore, time variability in accumulation seasonality can weaken or strengthen the accumulation-weighting hypothesis, depending on the time evolution of the seasonality changes.