The fall of 2006 was the warmest on record in Europe. So far the origins of this seasonal extreme anomaly have not been elucidated, but understanding them is crucial since climate change may increase the frequency and amplitude of such extreme seasons. From a statistical analysis and regional modeling experiments we estimate the contributions of regional atmospheric circulation and sea-surface temperatures (SST) on the continental surface temperatures of this event. Both the regression and the dynamical model attribute about 50% of the land temperature anomaly to the atmospheric flow conditions, 30% to the SST warm anomaly, while the missing 20% remain unexplained. Assuming such decomposition, the contribution of trend components would explain about 20 to 40% of the anomaly, a proportion that should increase in the future.