Several widespread tree species of temperate forests produce recalcitrant (desiccation-sensitive) seeds, but the ecological significance of this is largely unknown. Using Quercus ilex (holm oak) woodlands in France as a model system, Joët et al. study relationships between winter climate and the water status and viability of seeds in the spring. They find that percentage germination and normal seedling development are tightly linked to the water content of seeds after the winter period, indicating that in situ desiccation is a major cause of mortality: cumulative rainfall and maximum temperatures during winter dramatically influence the water status and viability of seeds. They conclude that seed desiccation sensitivity is a key functional trait that may influence the success of recruitment in temperate recalcitrant seed species, particularly within the context of future climate change.