The share of each ensemble's members in the seven year-round Atlantic–European weather regimes of Grams et al. (2017), each day: their 500 hPa height over 80° W–40° E, 30–90° N, 10-day low-pass filtered, projected on the regimes as updated to ERA5 by C. M. Grams (data: Zenodo, CC BY 4.0). A member is in the regime of the highest index above 1, else in none (single days, without the life-cycle criteria). ECMWF grows upward from the dates, GEFS downward. The dot on each day: the regime more than half of both models' members share (two halves where the models differ, a ring where neither has one).