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Using an international, multi‐model suite of historical forecasts from the World Climate Research Programme (WCRP) Climate‐system Historical Forecast Project (CHFP), we compare the seasonal prediction skill in boreal wintertime between models that resolve the stratosphere and its dynamics (‘high‐top’) and models that do not (‘low‐top’). We evaluate hindcasts that are initialized in November, and examine the model biases in the stratosphere and how they relate to boreal wintertime (December–March) seasonal forecast skill. We are unable to detect more skill in the high‐top ensemble‐mean than the low‐top ensemble‐mean in forecasting the wintertime North Atlantic Oscillation, but model performance varies widely. Increasing the ensemble size clearly increases the skill for a given model. We then examine two major processes involving stratosphere–troposphere interactions (the El Niño/Southern Oscillation …