Relief map of the Burgundy-Franche-Comté region (black bold line) and location of the Météo-France climate stations (grey circles) used for both daily spatial interpolation of temperatures and computation of frost stress level. Note that the circle size is reversely proportional to the missing data in the climate series. Red cross corresponds to the pea crop experimental site located at Chaux-des-Prés. Altitude is given in metres above sea level. Elevated areas in the South-East of the map correspond to the Alps mountains.