“…We used multi‐model ensemble data of six seasonal prediction systems (specifications in Table S1 in Supporting Information ): the European Centre for Medium‐Range Weather Forecasts fifth‐generation seasonal forecast system (SEAS5, Johnson et al., 2019), the United Kingdom Met Office Global Seasonal Forecast System version 5 (GloSea5, MacLachlan et al., 2015), Météo‐France System 7 (MF‐S7), the German Climate Forecast System 2.0 (GCFS2.0, Fröhlich et al., 2021), the Euro‐Mediterranean Center on Climate Change Seasonal Prediction System 3 (CMCC‐SPS3, Sanna et al., 2017), and the Japan Meteorological Agency/Meteorological Research Institute Coupled Prediction System version 2 (JMA/MRI‐CPS2, Takaya et al., 2018). Focusing mainly on winter conditions (December–February: DJF), we analyzed monthly mean data of 6‐month hindcasts initialized around 1 November between 1993 and 2016 (dates of initialization differ among the models).…”