A sudden cold exposure (4 °C, 24 h) primes the resistance of Arabidopsis thaliana against the virulent biotrophic pathogen Pseudomonas syringae pv. tomato DC3000 (Pst) for several days. This effect is mediated by chloroplast cold sensing and activity of stromal and thylakoid-bound ascorbate peroxidases (sAPX/tAPX). In this study, we investigated the impact of cold exposure on plant defences against the necrotrophic fungus Botrytis cinerea and compared plant responses to this pathogen in sapx and tapx single knockout lines. Plant resistance was transiently enhanced if B. cinerea infection occurred immediately after cold exposure, but cold-enhanced B. cinerea resistance was absent when cold treatment and infection were separated by 5 days under normal growth conditions. Plastid ascorbate peroxidases partially contributed to the transient cold-enhanced resistance against the necrotrophic fungus. In response to B. cinerea, the levels of reactive oxygen species (ROS) were significantly higher in cold-pretreated Arabidopsis leaves. Pathogen-triggered ROS levels varied without sAPX, highlighting the strong capacity of sAPX-dependent ROS regulation in the chloroplast stroma. The cold-enhanced resistance against B. cinerea was associated with cold-induced plant cell wall modifications, including sAPX-dependent callose formation and significant lignification in cold-treated Arabidopsis leaves.